Answer:
g=3
Step-by-step explanation:
f(g) = g^2 +3g
Let f(g) = 18
18 = g^2 +3g
Subtract 18 from each side
18-18 =g^2 +3g-18
0 = g^2 +3g-18
Factor
0 = (g+6) (g-3)
Using the zero product property
g+6 =0 g-3 =0
g = -6 g =3
The only solution listed is g=3
