How do we do the following equation.

3x^2+28x+9=0

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