Download answers - Mr. Trenfield Math

NAME
DATE
4-3
PERIOD
Practice
Solving Quadratic Equations by Factoring
Write a quadratic equation in standard form with the given root(s).
1. 7, 2
2. 0, 3
x 2 - 9x + 14 = 0
4. -7, -8
3. -5, 8
x 2 - 3x = 0
6. 3, -4
5. -6, -3
2
x + 15x + 56 = 0
2
x + 9x + 18 = 0
1
7. 1, −
1
8. −
,2
2
2
2
x 2 + x - 12 = 0
7
9. 0, - −
3
2x - 3x + 1 = 0
x 2 - 3x - 40 = 0
2
2
3x - 7x + 2 = 0
2x + 7x = 0
Factor each polynomial.
10. r3 + 3r2 - 54r
r (r + 9)(r - 6)
13. x3 + 8
11. 8a2 + 2a - 6
2(4a - 3)(a + 1)
14. 16r2 - 169
(x + 2)(x 2 - 2x + 4)
12. c2 - 49
(4r + 13)(4r - 13)
(c - 7)(c + 7)
15. b4 - 81
(b 2 + 9)(b + 3)(b - 3)
Solve each equation by factoring.
17. x2 - 16x + 64 = 0 {8}
18. x2 - 6x + 8 = 0 {2, 4}
19. x2 + 3x + 2 = 0 {-2, -1}
20. x2 - 4x = 0 {0, 4}
21. 7x2 = 4x
22. 10x2 = 9x
9
0, −
10 0, −47 23. x2 = 2x + 99 {-9, 11}
24. x2 + 12x = -36 {-6}
25. 5x2 - 35x + 60 = 0 {3, 4}
−56 , - −56 27. 2x2 - 8x - 90 = 0 {9, -5}
26. 36x2 = 25
28. NUMBER THEORY Find two consecutive even positive integers whose product is 624.
24, 26
29. NUMBER THEORY Find two consecutive odd positive integers whose product is 323.
17, 19
30. GEOMETRY The length of a rectangle is 2 feet more than its width. Find the
dimensions of the rectangle if its area is 63 square feet. 7 ft by 9 ft
31. PHOTOGRAPHY The length and width of a 6-inch by 8-inch photograph are reduced by
the same amount to make a new photograph whose area is half that of the original. By
how many inches will the dimensions of the photograph have to be reduced? 2 in.
Chapter 4
20
Glencoe Algebra 2
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
16. x2 - 4x - 12 = 0 {6, -2}