Lesson 8 - Loudoun County Public Schools

Answer Key Lesson 8.1 Practice Level A 1. direct variation 2. neither 3. inverse variation 4. inverse variation

6 5. y 5 } ​ x ​; 3 15 15 6. y 5 } ​  x  ​;} ​ 2  ​ 212 7. y 5 } ​  x     ​; 26 16 8. y 5 } ​  x  ​; 8 3 3 9. y 5 } ​ x ​;}2​  ​ 6 10. y 5 } ​ x ​; 3 11. direct variation 12. neither 13. inverse variation 14. neither 15. direct variation 16. inverse variation 17. z 5 4xy; 40 18. z 5 2xy; 20

1 19. z 5 } ​ 2 ​ xy; 5 20. 0.04 21. I 5 0.04tP 22. $240 23. The interest rate of the savings account.

Answer Key Lesson 8.2 Practice Level A 1. x 5 24 2. x 5 2 3. x 5 26

1 1 1 4. y 5 } ​ 2 ​; domain: all real numbers except 2​ }2 ​; range: all real numbers except } ​ 2 ​ 5. y 5 3; domain: all real numbers except 1; range: all real numbers except 3 6. y 5 24; domain: all real numbers except 0; range: all real numbers except 24 7. C 8. A 9. B 10.



13. C 5 8.5x 1 350

8.5x 1 350 14. A 5 } ​        ​ x 15.

11.

12.

Answer Key Lesson 8.3 Practice Level A 1. x-intercept: none; vertical asymptotes: x 5 22, x 5 2 2. x-intercept: 3; vertical asymptotes: x 5 22, x 5 4 } } 2 3. x-intercept: 2​ } ​; vertical asymptotes: x 5 2​Ï 3 ​,  x 5 Ï ​ 3 ​  3

4. x-intercept: none; vertical asymptote: x 5 0 5. x-intercepts: 3, 4; vertical asymptotes: x 5 26, x 5 6 }

}

6. x-intercepts: 2​Ï 5 ​,  ​Ï 5 ​ ; vertical asymptote: x 5 22 7. B 8. A 9. C 10.

11.

12.

13.

14.

15.

16. 20 ft by 40 ft

Answer Key Lesson 8.4 Practice Level A x 1. } ​ x 2 2 ​  x11 2. } ​ x 2 2   ​ 3. not possible

x23 4. } ​ x 1 2   ​ x11 5. } ​ x 2 4   ​ x24 6. } ​ x 1 5   ​ 9x 7. } ​  2  ​  2y 3y 2 8. } ​  2 ​  x 3 9. }} ​       ​  (x 1 3)(x 2 1) 10. (x 1 2)(x 2 1)

x 11. } ​ x 2 1 ​  (x 1 2)(x 2 6) 12. }} ​       ​  2(x 2 4) 16y 3 13. } ​  5    ​  14. 28x 2y

2x 15. } ​ x 2  2 ​  x23 16. } ​ x 1 3   ​ x 17. } ​ x 1 4  ​  2x 2 1 18. } ​ x 2 3   ​ 12(x 1 2) 19. ​ }       ​ x

Answer Key Lesson 8.5 Practice Level A 7 x23 4x 1. } ​ 2x  ​ 2. } ​ x 1 4   ​ 3. ​ }    ​  4. 5x x22 5. (x 1 2)(x 2 1) 6. (x 1 2)(x 2 2) 7. (x 2 1)(x 1 3) 8. 6x(x 1 3)

4x 1 9 5x 2 2 2x 1 4 9. 4x(x 2 1)(x 1 1) 10. } ​  2  ​    11. } ​    ​    6x 2x 2 23(x 1 2) 5x 2 7 12. ​ }}      ​ 13. ​ }     ​  x14 (x 1 1)(x 2 3) 2x 2 2 4x 1 7 x 2 2 x 1 12 4x 14. }} ​       ​ 15. }} ​       ​ 16. } ​ 2x 1 1 ​  (x 2 4)(x 1 2) (x 2 2)(x 1 2) 2(6 2 x) 2(3x 1 2) 17. } ​     ​ 18. ​ }}     ​  3(x 1 2) 2(x 2 2)(x 1 1) 3xy 19. z 5 } ​ y 1 2x   ​ 20. 5 mL

Answer Key Lesson 8.6 Practice Level A 1. no 2. yes 3. 24 4. 6 5. 23, 3

3 6. 22, } ​ 2 ​ 7. 23, 7 8. 0 9. 4, 5 10. 29, 2 11. 2 12. 25 13. 2 14. 26, 21

4 15. } ​ 7 ​ 16. no solution 3 17. 24, } ​ 2 ​ 18. 3 19. 4 mi, 8 mi 20. 21.9 mi/gal 21. $385.66