Solving Quadratics

Solve by factoring: x² - 9x + 20 = 0

• x = -4 and x = -5
• x = 20 and x = -9
• x = 4 and x = 5
• x = -4 and x = 5

Factor: 49x² - 100

• (49x + 100)(x - 1)
• (7x - 10)(7x + 10)
• (49x - 10)(x + 10)
• (7x -10)(7x - 10)

Factor:   3x²- 6x - 24

• (3x - 8)(x + 3)
• (3x + 4)(x - 6)
• 3(x - 2)(x + 4)
• 3(x + 2)(x - 4)

7x² - 26x - 8 = 0

• x = -1 and x = -7/8
• x = 4 and x = -2/7
• x = -4 and x = 2/7
• x = 4 and x = -7/2

(x + 1) ² = 25

• ± 5
• 4  or  -6
• -4  or  6
• ± 4

Solve 14 - x² = 17

• x = ±1.73
• x = 3
• no solution
• x = -3

Suzie solves the equation below:
x² + 4x - 12 = 2
(x - 2)(x + 6) = 2, 
by setting x -2 = 0 and x + 6 = 0. 
Her solutions are x = 2 and x = -6.
Is Suzie correct? Why or why not?

• Yes, she factored correctly and then used the zero product property
• Yes, she factored correctly and then square rooted.
• No, she did factor correctly, but she can't use the zero product property as shown.
• No, she didn't factor correctly so the rest of her work is wrong. 

When factoring
x² - 4x + 4 = 20,
what goes in the blank?
(x - __ )² = 20

• 4
• 2
• 8
• 20

Solve by method of your choice.

x² + 10x = -9

• 1 and -12

• -1 and -9

• 1 and -9

• 1 and -1