If X (ast) Y = X + Y – XY, find x when (x (ast) 2) + (x (ast) 3) = 68

A.
24 
B.
22 
C.
12 
D.
21
Correct Answer: Option D
Explanation
x (ast) y = x + y – xy
(x (ast) 2) + (x (ast) 3) = 68
= x + 2 – 2x + x + 3 – 3x
= 86
3x = 63
x = 21
x (ast) y = x + y – xy
(x (ast) 2) + (x (ast) 3) = 68
= x + 2 – 2x + x + 3 – 3x
= 86
3x = 63
x = 21