In order to calculate the composite function (gof)(x), we need to use f(x) as the input (value of x) of the function g(x).
So we have:
[tex]\begin{gathered} g(x)=4x+2\\ \\ g(f(x))=4f(x)+2\\ \\ g(f(x))=4(-3x+4)+2\\ \\ g(f(x))=-12x+16+2\\ \\ g(f(x))=-12x+18 \end{gathered}[/tex]
