Solving Quadratics by Factoring Unit 7c

What is the first step in solving 
(x + 2)(x - 3) = 0      ?

• Plug in zero for x
• Solve for x
• FOIL
• Set each binomial factor equal to zero

What are the two solutions to this quadratic that is already factored for you.

 $\left(3x+4\right)\left(x-9\right)=0$  

•  $x=-9,-4$  

•  $x=+\frac{4}{3},-9$  

•  $x=-\frac{4}{3},+9$  

•  $x=+3,+4$  

What should you do first in solving this equation?

x² + 6x - 13 = 3

• Get factored form

• Write down: a=1, b=6, c=-13

• Make it equal 0 by subtracting 3 on each side

• Type it all in a calculator.

Factor:  
x² -17x - 60

• (x - 20)(x + 3)
• (x - 3)(x + 20)
• (x - 3)(x - 20)
• (x + 3)(x + 20)

Factor and Solve

x² + 2x - 24 = 0

• x = -6, x = 4

• x = 6, x = -4

• x = 12, x = -2

• x = 8, x = -3

Factor and Solve

x² + 9x + 20 = 0

• x = -2, x = -10

• x = -3, x = -4

• x = -4, x = -5

• x = -4, x = -6

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

Solve the equation by factoring:

x² - 6x = -8

• x=2 and x=4

• x= -2 and x= -4

• x= -2 and x=4

• x=2 and x= -4

Factor and Solve

 $4x^2+32x+60=0$  

•  $x=+5,+8$  

•  $x=-8,-5$  

•  $x=7$  

•  $x=-5,-3$  

Solve by Factoring

 $x^2-49=0$  

•  $x=7$  

•  $x++7,+7$  

•  $x=-7,-7$  

•  $x=-7,+7$