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.