f(x)=3x+2, (gof)(x)=15x+9 maka g-¹(4)=...

f(x) = 3x + 2

g(f(x)) = 15x + 9
g(3x + 2) = 5(3x + 2) - 1
g(x) = 5x - 1
5x = g(x) + 1
x = (g(x) + 1)/5

g^-1 (x) = (x + 1)/5

g^-1 (x) = (x + 1)/5
g^-1 (4) = (4 + 1)/5
g^-1 (4) = 1 ✔