Answer :

F(x) and g(x) are basically =y
So if u sub f(x) and g(x) with y

Y= 18-3x
-18= -3x
X= 6
f(x) = 6

Y = 6- x/3
-6=x/3
X=18

G(x)= 18


The answer is:

f(x) = 6
g(x)=18