tentukan (gof) (x) dan (fog) (y) dari f (×)=3× g (×) = ×2 + 4×+18

[tex](gof)(x) = g(f(x)) \\ = g(3x) = {(3x)}^{2} + 4(3x) + 18 \\ = 9 {x}^{2} + 12x + 18 \\ [/tex]
[tex](fog)(x) = f(g(x)) \\ = f( {x}^{2} + 4x + 18) \\ = 3( {x}^{2} + 4x + 18) \\ = 3 {x}^{2} + 12x + 54[/tex]