Question

Check my work?
Given f(x) = x2 + 6x and g(x) = 3x2 + 12x, find (g – f)(x).
My answer:2x^2+18

Given f(x) = 7x – √2 and g(x) = x + √2, find (f + g)(x).
My answer:7 – √2x

Which of these is the composite function f(g(x))?
f(x) = x2 – 5
g(x) = 9x – 2
My answer:f(g(x)) = 81x2 – 36x – 1

Given f(x) = x2 – 4x – 2 and g(x) = 2x2 + 4x + 9, find (f – g)(x).
My Answer:-3x2 – 8x – 11

Given f(x) = 3x + 3 and g(x) = x2 + 11x – 7, find (gf)(x).
My Answer: 36x3 – 3x2 + 12x – 21