use ac methd
in form ax²+bx+c=0
to factor
1. multiply a and c
2. what does that result factor to to add to b?
3. split up b to make those facotrs
4. group
5. undistribute 2 times
3x²+28x+9=0
3 times 9=27
what 2 numbers multily to 27 and add to 28?
1 and 27
3x²+1x+27x+9=0
(3x²+1x)+(27x+9)=0
x(3x+1)+9(3x+1)=0
(3x+1)(x+9)=0
set to zero
3x+1=0
3x=-1
x=-1/3
x+9=0
x=-9
x=-1/3 or -9
