Question

Given the functions f(x) = 7x + 13 and g(x) = x + 2, which of the following functions represents f[g(x)] correctly?

f[g(x)] = 7x + 15
f[g(x)] = 7x + 27
f[g(x)] = 7x2 + 15
f[g(x)] = 7x2 + 27

Answer 1

If you want to find f[g(x)] just substitute "x+2" for an "x" in equation f(x)=7x+13. You'll get:

f[g(x)]= 7(x+2)+13=7x + 14 + 13 = 7x + 27

Choose second answer

Answer 2

B. f(g(x)) = 7x + 27

Explanation:

We have, f(x) = 7x+13 and g(x) = x+2.

So, the function f(g(x)) is obtained by substituting the function g(x) = x+2 in f(x) = 7x+13,

i.e. f(g(x)) = f(x+2)

i.e. f(g(x)) = 7 × (x+2) + 13

i.e. f(g(x)) = 7x + 14 + 13

i.e. f(g(x)) = 7x + 27

Thus, f(g(x)) = 7x + 27

Hence, option B is correct.