Question

If f(x) = x + 2 and g(x) = 3x +4, then (g °f)(x) = ?

a. 3x + 6

b. 3x + 10

c. 3x^2 + 6x + 4

d. 3x^2 + 10x + 6

Answer 1

The correct answer is a. 3x + 6

In order to find a compound function, you must use the first letter in the function (in this case f) and plug the second letter (g) in where you see x's.

f(x) = x + 2

f(g(x)) = (g(x)) + 2

f(g(x)) = (3x + 4) + 2

f(g(x)) = 3x + 6