Diketahui f(x) = x²+5x-4 dan g(x) = x+7 Tentukan: a. (gof)(x) b. (fog)(x)

a.g°f(x)
=g(f(x)
=g(x²+5x-4)
=x²+5x-4+7
=x²+5x+3

b.f°g(x)
=f(g(x)
=f(x+7)
=(x+7)²+5(x+7)-4
=x²+7x+7x+49+5x+35-4
=x²+7x+7x+5x+49+35-4
=x²+19x+80