F(x)=x-1.9(x)=x2+2x-3 tentukan gof(x)

f(x) = x-1
g(x) = x²+2x-3

gof(x) = g(f(x))
         = (x-1)²+2(x-1)-3
         = x²-2x+1+2x-2-3
         = x²-4