tolonggg kalau ada yang bisa bantu yaa...

(fog)(x)= x^2-4 g(x)= (x+1)^1/2
f(g(x))= x^2-4
f((x+1)^1/2))= x^2 -4

(x+1)^1/2=y => x = y^2-1

f(y) = (y^2-1)^2-4
f(y) = y^4-2y^2+1-4
f(y) = y^4-2y^2-3
f(x) = x^4-2x^2-3