section 9.3 - factoring trinomials (part 2)

9.3 continued
Zero- product property
If a*b=0, then one or both of the factors has to = 0
Ex) solve for x

X(2x+1)=0
2x^2=0 or x=0
x=-.5 or x=o
-1/2(2(-1/2)+1)=0
-1/2(-1+1)=0
-1/2(0)= 0

x^2 +5x+4=0
(x+1)(x+4)= 0
x=-1 x=-4

x^2+8x=20
-20 -20

x^2+8x-20=0
(x-2)(x+10)=0
x=2 x=-10

solve for a

a^2=6q-8

a^2-6a+8=0

a=2 a=4