Answer:
a=-2
Explanation:
in order to factor, you need to multiply the constant (12) and the number with the square root (3)
12*3=36
you have to find two numbers that multiply to get 36 and add to get 12
6 and 6 both work for this
3a^2+6a+6a+12
find the GCF
3a(a+2) 6(a+2)
(3a+6) = 0
(a+2) = 0
a=-2