Solving quadratics by Factoring

Solve
x² + 9x + 20 = 0

• x = -2, x = -10
• x = -3, x = -4
• x = -4, x = -5
• x = -4, x = -6

Solve
x² + 2x - 24 = 0

• x = -6, x = 4
• x = 6, x = -4
• x = 12, x = -2
• x = 8, x = -3

Solve
x² + 13x + 12 = 0

• x = -1, x = -12
• x = -1, x = -24
• x = -2, x = -6
• x = -2, x = -12

Solve by Factoring

 $x^2-49=0$  

•  $x=7$  

•  $x++7,+7$  

•  $x=-7,-7$  

•  $x=-7,+7$  

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.

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

Solve:   $3x^2=9x$  

•  $x=3$  and  $x=-3$  

•  $x=3$  

•  $x=0$  and  $x=9$  

•  $x=0$  and  $x=3$