Math Multiple Choice
If xy = 2 and xy 2 = 8, what is the value of x ?
- (A) CORRECT ANSWER
- (B) 2
- (C) 4
- (D) 8
- (E) 16
Substituting xy = 2 into the equation xy2 = 8, you will obtain (xy)y = 2y = 8, thus y = 4. To find x, substitute y = 4 into one of the two original equations to obtain x = . The answer to this problem is (A).
(from the October 17, 1998 test)