If f (x) = x + 1 and g (x) = 2x - 7, which expression is equivalent to [f o g] (3) ?

A. (3 + 1) (2 (3) - 7)

B. 2 (3) 2 - 6

C. 2 (3 + 1) - 7

D. (2 (3) - 7) + 1

To answer the question above, substitute the x from the function f (x) with the expression of g (x). That is,

[f o g] (x) = (2x - 7) + 1

Then, substitute 3 to the x's in the function above.

[f o g] (3) = (2 (3) - 7) + 1

The answer should be letter D.