The Correct answer is C.
Explanation
Recall that
can be factored as
. Since
and
, their product,
, is
, or
.
Another method of solution is to solve the two equations
and
simultaneously to get
and
. Then
is
.

Mathematics > Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
If
and
, then 
(A) 4
(B) 8
(C) 15
(D) 16
(E) 64