Suppose f(x)=x2+4 and g(x)=3xg(f(x)) would therefore be 3(x2+4) and that equals 3x2+12the next step would then be to substitute x with 1 to find the solution for (g(f(1)).By substituting 1 for x, you then use BODMAS to solve the equation. 3(1)2+12 would therefore equal 15 so g(f(1)) is 15.