Friday, February 17, 2006

PS - bi-variant function

If x * y = xy - 2(x+y) for all integers x and y, then 2 * (-3) = ...

(A) -16
(B) -11
(C) -4
(D) 4
(E) 16

1 comment:

Luís Botelho Ribeiro said...

We just have to compute the second member expression, with x=2 and y=-3. THus 2X(-3)-2[2+ (-3)] = -6 -2X[-1]=-6 + 2 = -4.

:. correct answer is (C)