Algebra 1 Practice Test

Algebra 1 Practice Test Answer Key

Copyright © Karin Hutchinson, 2011. All rights reserved. Please respect the time, effort, and careful planning spent to prepare these materials. The distribution of this e-book via the internet or via any other means is illegal and punishable by law. Please purchase only authorized copies via Algebra-class.com and do not participate in piracy of copyrighted materials. Your support of the authors’ rights is appreciated. Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Answer Key

Part 1: Multiple Choice 1. B 2. A 3. C 4. C 5. B 6. C 7. D 8. A 9. A 10. C 11. A 12. C 13. B 14. B 15. B 16. D 17. A 18. C 19. C 20. A Part 2: Short Answer 21. There is a maximum point. The vertex is (-2, -2)

22. The factors are: (4x+1)(2x-3)

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test 23. The solution is (-3,-3)

The solution: (-3, -3)

24. x = 1.6 and x = -5.6

25. x intercepts: x=2 and x = -2

vertex: (0,-4)

26. x2 – 14x + 49 27. The discriminant is 1. There are 2 rational solutions. Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Part 3: Extended Response 28. Wireless Plus: y = .10x + 65 New Age Phone: y = .20x + 35 For 300 gigabytes over the monthly limit, the 2 plans will charge the same amount ($95) For 200 gigabytes over the monthly limit, New Age Phones is the better value. They only charge $75 versus Wireless Plus who charges $85. 29.

The equation that can be used to predict the profit is: Y = 2758.89 + 35700. In the year 2011, the profit will be $93636.69. The y-intercept represents the profit for year 0, which in this case is 1990.

30. The candy store must sell 2115 boxes of candy in order to maximize its profit. The maximum profit would be $5017.31 31. The width of the rectangle is 26 units. 32. The system of inequalities that represents this situation is: Let x = number of cheese pizzas Let y = number of supreme pizzas 12x + 15y ≥ 1000 (purple line and shading) x+y ≤ 120 (orange line and shading)

If 75 cheese pizzas were sold, then up to 45 supreme pizzas could be sold in order to make at least $1000. Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Algebra Practice Test Analysis Sheet Directions: For any problems, that you got wrong on the answer sheet, circle the number of the problem in the first column. When you are finished, you will be able to see which Algebra units you need to review before moving on. (If you have more than 2 circles for any unit, you should go back and review the examples and practice problems for that particular unit!) Problem Number

Algebra Unit

1,17

Unit 1: Solving Equations

2, 15

Unit 2: Graphing Equations

6,19, 29

Unit 3: Writing Equations

2, 12, 23, 28

Unit 4: Systems of Equations

3, 4, 13, 32

Unit 5: Inequalities

11, 21

Unit 6: Relations & Functions

7, 14

Unit 7: Exponents & Monomials

8, 16, 26,31

Unit 8: Polynomials

10, 18, 22

Unit 9: Factoring (Polynomials)

5, 9, 20, 24, 25, 27, 30

Unit 10: Quadratic Equations

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Algebra Practice Test Step-by-Step Solutions Part 1: Directions: For questions 1-20, circle the correct answer on your answer sheet. 1. Solve for x: A. B. C. D.

x=5 x = 11 x = -11 x = -5

2(x+ 7) – 3(2x-4) = -18 2(x+ 7) – 3(2x-4) = -18

Original Problem

2x + 14 – 6x + 12 = -18

Distribute the 2 and the -3 throughout the parenthesis.

2x – 6x + 14 + 12 = -18

Write like terms together.

-4x + 26 = -18

Combine like terms.

-4x + 26 – 26 = -18 – 26

Subtract 26 from both sides.

-4x = -44

Simplify: -18-26 = -44

-4x/-4 = -44/-4

Divide by -4 on both sides.

x = 11

x = 11 is the final answer.

2. Which system of equations is represented on the graph? A. y= 2x – 2 y = -1/3x + 5 B. y = 1/2x – 2 y = 1/3x + 5 C. y = 2x – 2 y = 1/3x + 5 D. y = -2x -2 y = -1/3x +5 Since all of the answer choices are written in slope intercept form, we can identify the slope and y-intercept for each line and then write an equation for each line. Slope Intercept Form: y = mx + b (m=slope, b = y-intercept) Red Line: Slope (m) = 2 y-intercept (b) = -2 Equation: y = 2x – 2 Blue Line: Slope (m) = -1/3x y-intercept (b) = 5 Equation: y = -1/3x + 5 A is the correct answer choice. Copyright © 2011 Karin Hutchinson – Algebra-class.com

TIP: You know the red line has a positive slope because it’s rising from left to right. The blue line has a negative slope because it’s falling from left to right. Therefore, we can eliminate answer choices B, C, and D because B and C have two equations with both positive slopes and letter D has two equations with both negative slopes. The only answer choice with a positive and a negative slope is A.

Algebra 1 Practice Test 3. Solve the following inequality: -20 < 4 – 2x

A. 8 > x B. 8 < x

C. 12 > x D. 12 < x

-20 < 4 – 2x

Original Problem

-20 – 4 < 4-4-2x

Subtract 4 from both sides to isolate the variable on one side of the equation.

-24 < -2x

Simplify: -20-4 = -24

-24 / -2 x

Simplify: -24/-2 AND Remember: Whenever you multiply or divide by a negative number when working with an inequality, you must reverse the symbol! Therefore, the less than symbol is reversed to a greater than symbol because I divided by -2 on both sides. (This only applies to multiplication and/or division by a negative number when working with inequalities.)

The correct answer is C: 12> x

4. Which inequality is graphed ? A. y ≥ 2x+2 B. y < 2x+2 C. y ≤ 2x +2 D. y ≤ -2x+2 We know that the slope is positive because the line is rising from left to right, so we can eliminate letter D since its slope is negative 2. y ≤ -2x+2 We also know that the line graphed is a solid line. This means that the symbol used must be ≤ or ≥. (If the line were dotted, then the symbol would be < or >). Therefore, we can eliminate letter B. We have choices A and C to choose from and both equations are the same. Therefore, we need to figure out which sign is correct by analyzing the shaded portion of the graph. We shade the portion of the graph that contains solutions to the inequality, so let’s pick a point in the shaded region.(0,0) is the easiest point to substitute and it’s in the shaded region. Let’s substitute (0,0) into the equation see which symbol produces Copyright © 2011 Karinand Hutchinson – Algebra-class.com a true statement.

0 ___ 2(0) + 2 0≤ 2

Since the left side = 0 and the right side equals 2, we know that 0 is less than 2. Therefore, we must use the less than or equal to symbol. This means that letter C is the correct answer choice.

Algebra 1 Practice Test 5. Which equation is represented on the graph? A. y = x2 + 13x +36 B. y = x2 -13x +36 C. y = x2 +5x - 36 D. y = x2 -5x + 36 We know that since there is a parabola graphed that this is a quadratic equation. From looking at the graph we know that the x-intercepts are 4 and 9. The x-intercepts always have a y coordinate of 0. We also know that when we let y = 0, we can factor the equation and use the zero product property to find the x-intercepts. Therefore, we will work backwards. 0 = (x -4) (x-9) (Using the zero product property, we would have x – 4 = 0 and x -9 =0 So, x = 4 and x = 9. This proves that this equation would be correct since these are the xintercepts.

Since the factors are (x-4)(x-9), let’s multiply to see what the original equation would be: Using foil: (x-4)(x-9) x(x) + x(-9) + -4(x) + (-4)(-9) x2 – 9x – 4x + 36 x2 – 13x + 36 Therefore, the correct choice is B.

6. John has mowed 3 lawns. If he can mow 2 lawns per hour, which equation describes the number of lawns, m , he can complete after h, more hours? A. m + h = 5 B. h = 2m + 3 C. m = 2h + 3 D. m = 3h + 2

The first thing you should recognize is the key word for slope, per. Since John can mow 2 lawns per hour, we know that this is the slope (m). Also, since the problem states per hour, we know that the variable associated with the slope is h. At this point, I realize that the only problem that has, 2h is letter b. Let’s see if it makes sense. He has also mowed 3 lawns, this is a constant so this would be the y-intercept. Therefore, we have: m = 2h + 3. This means that the number of lawns mowed (m) equals 2 lawns per hour + the 3 lawns that he already mowed. Yes, it makes sense, so the correct response is letter C.

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test

7. Simplify: (-3a2b2)(4a5b3)3 (-3a2b2)(4a5b3)3

Original Problem

(-3a2b2)(64a15b9)

Complete Power of a Power first. (Multiply exponents when raising a power to a power.)

-192a17b11

Multiply: When multiplying powers you add the exponents. The answer is: D

A. -192a8b5

C. -12a8b5

B. -12a17b11

D. -192a17b11

8. Multiply: (2x+5)(3x2 – 2x - 4) We must use the extended distributive property in order to multiply. First distribute 2x, then we will distribute 5. 2x(3x2) +2x(-2x) + 2x(-4) + 5(3x2) + 5(-2x) + 5(-4) 6x3

-4x2

– 8x

+ 15x2

– 10x

- 20

6x3 – 4x2 + 15x2 – 8x – 10x – 20 6x3 + 11x2

– 18x – 20

Rewrite with like terms together. Combine like terms and this is the final answer. The answer is: A

A. 6x3 + 11x2 - 18x - 20

C. 21x2 + 22x - 20

B. 6x3 + 19x2 +18x +20

D. 6x3 +15x2 + 6x +12

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test

9. Which polynomial cannot be factored? The easiest way to determine whether or not a polynomial can be factored is to find the discriminant. If the discriminant is a perfect square, then the polynomial can be factored. If the discriminant is negative or not a perfect square, then it cannot be factored. So, we are looking for the polynomial that has a negative or non-perfect discriminant. The formula for the discriminant is: b2 – 4ac when given: ax2 + bx + c. We’ll need to pick an answer choice and check: A. 3x2 – 14x −8 a=3

b = -14 c = -8

Discriminant: (-14)2 – 4(3)(-8) = 292

TIP: Just to check, if you find the discriminant for B, C, and D, you will find them all to be perfect squares.

Since the discriminant is not a perfect square, this must be the answer.

A. 3x2 −14x − 8

C. 3x2 −14x + 8

B. 3x2 -10x −8

D. 3x2 + 10x – 8

10. What is the greatest common factor of: 12a4b2 – 3a2b5?

A. B. C. D.

12a2b2 3a4b5 3a2b2 12a4b5

We must find the greatest common factor for each part: the numerals, the a terms and the b terms. The greatest common factor of 12 and 3 is 3. The greatest common factor of a4 and a2 is a2 The greatest common factor of b2 and b5 is b2. Therefore the greatest common factor is: 3a2b2

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test 11. Given f(x) = 5x - 4, find the value of x if f(x) = 31 The problem says that f(x) = 31, so we must first substitute 31 for f(x) in this function. f(x) = 5x-4 31 = 5x- 4 31 + 4 = 5x – 4+4 35 = 5x 35/5 = 5x/5 X=7

Substitute 31 for f(x). Now solve for x. Add 4 to both sides. Simplify: 31 + 4 = 35 Divide by 5 on both sides. x = 7 is the final answer.

A. 7 B. 27/5

12.

C. 151 D. -7

Which answer best describes the number of solutions for the following system of equations? 4x+y = 5 8x+2y = -6

First we need to solve the system of equations in order to determine how many solutions it will have. Since we don’t have graph paper to graph the system, we will need to use the substitution method or linear combinations (the addition method). I am going to solve the first equation for y and use the substitution method. 4x+ y = 5 y = -4x + 5

4x-4x + y = -4x + 5 and 8x + 2y = -6

Solve for y by subtracting 4x from both sides. We can now substitute -4x+5 for y into the second equation.

8x+ 2(-4x+5) = -6

Substitute -4x+5 for y into the second equation.

8x – 8x + 10 = -6

Distribute the 2 throughout the parenthesis.

10 = -6

Since I have 8x-8x (which equals 0) on the left side, I am left with 10 = -6

This statement is not a true statement and I must stop here. Since this statement is not true, this means that there are no solutions to this system of equations. (These two lines are parallel) (If there were no variable at the end, but it was a true statement then the system would have infinitely many solutions.) If you ended up with x = ___ (a number), then there would be one solution.

A. 1 solution

C. no solutions

B. 2 solutions

D. infinitely many solutions

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test

13. Which graph best represents the solution set of: 15 – 2(x+3) < -7? We must first solve the inequality in order to determine which graph best represents the solution set. 15 – 2(x+3) < -7

Original problem

15 – 2x – 6< -7

Distribute the -2 throughout the parenthesis.

15 – 6 – 2x < -7

Rewrite with like terms together on the left hand side.

9 – 2x < -7

Simplify: 15 – 6 = 9

9-9-2x < -7 – 9

Subtract 9 from both sides.

-2x < - 16

Simplify: -7 – 9 = -16

-2x/-2 8

Simplify: -16/-2 = 8 Remember: You must reverse the inequality symbol when you multiply or divide by a negative number. (We divided by -2).

Note: Since our inequality symbol is

Algebra 1 Practice Test Answer Key

Copyright © Karin Hutchinson, 2011. All rights reserved. Please respect the time, effort, and careful planning spent to prepare these materials. The distribution of this e-book via the internet or via any other means is illegal and punishable by law. Please purchase only authorized copies via Algebra-class.com and do not participate in piracy of copyrighted materials. Your support of the authors’ rights is appreciated. Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Answer Key

Part 1: Multiple Choice 1. B 2. A 3. C 4. C 5. B 6. C 7. D 8. A 9. A 10. C 11. A 12. C 13. B 14. B 15. B 16. D 17. A 18. C 19. C 20. A Part 2: Short Answer 21. There is a maximum point. The vertex is (-2, -2)

22. The factors are: (4x+1)(2x-3)

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test 23. The solution is (-3,-3)

The solution: (-3, -3)

24. x = 1.6 and x = -5.6

25. x intercepts: x=2 and x = -2

vertex: (0,-4)

26. x2 – 14x + 49 27. The discriminant is 1. There are 2 rational solutions. Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Part 3: Extended Response 28. Wireless Plus: y = .10x + 65 New Age Phone: y = .20x + 35 For 300 gigabytes over the monthly limit, the 2 plans will charge the same amount ($95) For 200 gigabytes over the monthly limit, New Age Phones is the better value. They only charge $75 versus Wireless Plus who charges $85. 29.

The equation that can be used to predict the profit is: Y = 2758.89 + 35700. In the year 2011, the profit will be $93636.69. The y-intercept represents the profit for year 0, which in this case is 1990.

30. The candy store must sell 2115 boxes of candy in order to maximize its profit. The maximum profit would be $5017.31 31. The width of the rectangle is 26 units. 32. The system of inequalities that represents this situation is: Let x = number of cheese pizzas Let y = number of supreme pizzas 12x + 15y ≥ 1000 (purple line and shading) x+y ≤ 120 (orange line and shading)

If 75 cheese pizzas were sold, then up to 45 supreme pizzas could be sold in order to make at least $1000. Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Algebra Practice Test Analysis Sheet Directions: For any problems, that you got wrong on the answer sheet, circle the number of the problem in the first column. When you are finished, you will be able to see which Algebra units you need to review before moving on. (If you have more than 2 circles for any unit, you should go back and review the examples and practice problems for that particular unit!) Problem Number

Algebra Unit

1,17

Unit 1: Solving Equations

2, 15

Unit 2: Graphing Equations

6,19, 29

Unit 3: Writing Equations

2, 12, 23, 28

Unit 4: Systems of Equations

3, 4, 13, 32

Unit 5: Inequalities

11, 21

Unit 6: Relations & Functions

7, 14

Unit 7: Exponents & Monomials

8, 16, 26,31

Unit 8: Polynomials

10, 18, 22

Unit 9: Factoring (Polynomials)

5, 9, 20, 24, 25, 27, 30

Unit 10: Quadratic Equations

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test Algebra Practice Test Step-by-Step Solutions Part 1: Directions: For questions 1-20, circle the correct answer on your answer sheet. 1. Solve for x: A. B. C. D.

x=5 x = 11 x = -11 x = -5

2(x+ 7) – 3(2x-4) = -18 2(x+ 7) – 3(2x-4) = -18

Original Problem

2x + 14 – 6x + 12 = -18

Distribute the 2 and the -3 throughout the parenthesis.

2x – 6x + 14 + 12 = -18

Write like terms together.

-4x + 26 = -18

Combine like terms.

-4x + 26 – 26 = -18 – 26

Subtract 26 from both sides.

-4x = -44

Simplify: -18-26 = -44

-4x/-4 = -44/-4

Divide by -4 on both sides.

x = 11

x = 11 is the final answer.

2. Which system of equations is represented on the graph? A. y= 2x – 2 y = -1/3x + 5 B. y = 1/2x – 2 y = 1/3x + 5 C. y = 2x – 2 y = 1/3x + 5 D. y = -2x -2 y = -1/3x +5 Since all of the answer choices are written in slope intercept form, we can identify the slope and y-intercept for each line and then write an equation for each line. Slope Intercept Form: y = mx + b (m=slope, b = y-intercept) Red Line: Slope (m) = 2 y-intercept (b) = -2 Equation: y = 2x – 2 Blue Line: Slope (m) = -1/3x y-intercept (b) = 5 Equation: y = -1/3x + 5 A is the correct answer choice. Copyright © 2011 Karin Hutchinson – Algebra-class.com

TIP: You know the red line has a positive slope because it’s rising from left to right. The blue line has a negative slope because it’s falling from left to right. Therefore, we can eliminate answer choices B, C, and D because B and C have two equations with both positive slopes and letter D has two equations with both negative slopes. The only answer choice with a positive and a negative slope is A.

Algebra 1 Practice Test 3. Solve the following inequality: -20 < 4 – 2x

A. 8 > x B. 8 < x

C. 12 > x D. 12 < x

-20 < 4 – 2x

Original Problem

-20 – 4 < 4-4-2x

Subtract 4 from both sides to isolate the variable on one side of the equation.

-24 < -2x

Simplify: -20-4 = -24

-24 / -2 x

Simplify: -24/-2 AND Remember: Whenever you multiply or divide by a negative number when working with an inequality, you must reverse the symbol! Therefore, the less than symbol is reversed to a greater than symbol because I divided by -2 on both sides. (This only applies to multiplication and/or division by a negative number when working with inequalities.)

The correct answer is C: 12> x

4. Which inequality is graphed ? A. y ≥ 2x+2 B. y < 2x+2 C. y ≤ 2x +2 D. y ≤ -2x+2 We know that the slope is positive because the line is rising from left to right, so we can eliminate letter D since its slope is negative 2. y ≤ -2x+2 We also know that the line graphed is a solid line. This means that the symbol used must be ≤ or ≥. (If the line were dotted, then the symbol would be < or >). Therefore, we can eliminate letter B. We have choices A and C to choose from and both equations are the same. Therefore, we need to figure out which sign is correct by analyzing the shaded portion of the graph. We shade the portion of the graph that contains solutions to the inequality, so let’s pick a point in the shaded region.(0,0) is the easiest point to substitute and it’s in the shaded region. Let’s substitute (0,0) into the equation see which symbol produces Copyright © 2011 Karinand Hutchinson – Algebra-class.com a true statement.

0 ___ 2(0) + 2 0≤ 2

Since the left side = 0 and the right side equals 2, we know that 0 is less than 2. Therefore, we must use the less than or equal to symbol. This means that letter C is the correct answer choice.

Algebra 1 Practice Test 5. Which equation is represented on the graph? A. y = x2 + 13x +36 B. y = x2 -13x +36 C. y = x2 +5x - 36 D. y = x2 -5x + 36 We know that since there is a parabola graphed that this is a quadratic equation. From looking at the graph we know that the x-intercepts are 4 and 9. The x-intercepts always have a y coordinate of 0. We also know that when we let y = 0, we can factor the equation and use the zero product property to find the x-intercepts. Therefore, we will work backwards. 0 = (x -4) (x-9) (Using the zero product property, we would have x – 4 = 0 and x -9 =0 So, x = 4 and x = 9. This proves that this equation would be correct since these are the xintercepts.

Since the factors are (x-4)(x-9), let’s multiply to see what the original equation would be: Using foil: (x-4)(x-9) x(x) + x(-9) + -4(x) + (-4)(-9) x2 – 9x – 4x + 36 x2 – 13x + 36 Therefore, the correct choice is B.

6. John has mowed 3 lawns. If he can mow 2 lawns per hour, which equation describes the number of lawns, m , he can complete after h, more hours? A. m + h = 5 B. h = 2m + 3 C. m = 2h + 3 D. m = 3h + 2

The first thing you should recognize is the key word for slope, per. Since John can mow 2 lawns per hour, we know that this is the slope (m). Also, since the problem states per hour, we know that the variable associated with the slope is h. At this point, I realize that the only problem that has, 2h is letter b. Let’s see if it makes sense. He has also mowed 3 lawns, this is a constant so this would be the y-intercept. Therefore, we have: m = 2h + 3. This means that the number of lawns mowed (m) equals 2 lawns per hour + the 3 lawns that he already mowed. Yes, it makes sense, so the correct response is letter C.

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test

7. Simplify: (-3a2b2)(4a5b3)3 (-3a2b2)(4a5b3)3

Original Problem

(-3a2b2)(64a15b9)

Complete Power of a Power first. (Multiply exponents when raising a power to a power.)

-192a17b11

Multiply: When multiplying powers you add the exponents. The answer is: D

A. -192a8b5

C. -12a8b5

B. -12a17b11

D. -192a17b11

8. Multiply: (2x+5)(3x2 – 2x - 4) We must use the extended distributive property in order to multiply. First distribute 2x, then we will distribute 5. 2x(3x2) +2x(-2x) + 2x(-4) + 5(3x2) + 5(-2x) + 5(-4) 6x3

-4x2

– 8x

+ 15x2

– 10x

- 20

6x3 – 4x2 + 15x2 – 8x – 10x – 20 6x3 + 11x2

– 18x – 20

Rewrite with like terms together. Combine like terms and this is the final answer. The answer is: A

A. 6x3 + 11x2 - 18x - 20

C. 21x2 + 22x - 20

B. 6x3 + 19x2 +18x +20

D. 6x3 +15x2 + 6x +12

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test

9. Which polynomial cannot be factored? The easiest way to determine whether or not a polynomial can be factored is to find the discriminant. If the discriminant is a perfect square, then the polynomial can be factored. If the discriminant is negative or not a perfect square, then it cannot be factored. So, we are looking for the polynomial that has a negative or non-perfect discriminant. The formula for the discriminant is: b2 – 4ac when given: ax2 + bx + c. We’ll need to pick an answer choice and check: A. 3x2 – 14x −8 a=3

b = -14 c = -8

Discriminant: (-14)2 – 4(3)(-8) = 292

TIP: Just to check, if you find the discriminant for B, C, and D, you will find them all to be perfect squares.

Since the discriminant is not a perfect square, this must be the answer.

A. 3x2 −14x − 8

C. 3x2 −14x + 8

B. 3x2 -10x −8

D. 3x2 + 10x – 8

10. What is the greatest common factor of: 12a4b2 – 3a2b5?

A. B. C. D.

12a2b2 3a4b5 3a2b2 12a4b5

We must find the greatest common factor for each part: the numerals, the a terms and the b terms. The greatest common factor of 12 and 3 is 3. The greatest common factor of a4 and a2 is a2 The greatest common factor of b2 and b5 is b2. Therefore the greatest common factor is: 3a2b2

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test 11. Given f(x) = 5x - 4, find the value of x if f(x) = 31 The problem says that f(x) = 31, so we must first substitute 31 for f(x) in this function. f(x) = 5x-4 31 = 5x- 4 31 + 4 = 5x – 4+4 35 = 5x 35/5 = 5x/5 X=7

Substitute 31 for f(x). Now solve for x. Add 4 to both sides. Simplify: 31 + 4 = 35 Divide by 5 on both sides. x = 7 is the final answer.

A. 7 B. 27/5

12.

C. 151 D. -7

Which answer best describes the number of solutions for the following system of equations? 4x+y = 5 8x+2y = -6

First we need to solve the system of equations in order to determine how many solutions it will have. Since we don’t have graph paper to graph the system, we will need to use the substitution method or linear combinations (the addition method). I am going to solve the first equation for y and use the substitution method. 4x+ y = 5 y = -4x + 5

4x-4x + y = -4x + 5 and 8x + 2y = -6

Solve for y by subtracting 4x from both sides. We can now substitute -4x+5 for y into the second equation.

8x+ 2(-4x+5) = -6

Substitute -4x+5 for y into the second equation.

8x – 8x + 10 = -6

Distribute the 2 throughout the parenthesis.

10 = -6

Since I have 8x-8x (which equals 0) on the left side, I am left with 10 = -6

This statement is not a true statement and I must stop here. Since this statement is not true, this means that there are no solutions to this system of equations. (These two lines are parallel) (If there were no variable at the end, but it was a true statement then the system would have infinitely many solutions.) If you ended up with x = ___ (a number), then there would be one solution.

A. 1 solution

C. no solutions

B. 2 solutions

D. infinitely many solutions

Copyright © 2011 Karin Hutchinson – Algebra-class.com

Algebra 1 Practice Test

13. Which graph best represents the solution set of: 15 – 2(x+3) < -7? We must first solve the inequality in order to determine which graph best represents the solution set. 15 – 2(x+3) < -7

Original problem

15 – 2x – 6< -7

Distribute the -2 throughout the parenthesis.

15 – 6 – 2x < -7

Rewrite with like terms together on the left hand side.

9 – 2x < -7

Simplify: 15 – 6 = 9

9-9-2x < -7 – 9

Subtract 9 from both sides.

-2x < - 16

Simplify: -7 – 9 = -16

-2x/-2 8

Simplify: -16/-2 = 8 Remember: You must reverse the inequality symbol when you multiply or divide by a negative number. (We divided by -2).

Note: Since our inequality symbol is