tentukan (fog) dan (gof) jika : f(x)=x + 3 g(x)=3x + 4

f(g(x))
=(3x+4)+3
=3x+7

f(x) = x + 3
g(x) = 3x + 4

fog(x) = f(g(x))
          = f(3x + 4)
          = (3x + 4) + 3
          = 3x + 7

gof(x) = g(f(x))
          = g(x + 3)
          = 3(x + 3) + 4
          = 3x + 9 + 4
          = 3x + 13