If x = -2 and y = -4, what is the value of 5(x-y)^2 - xy ?  Choose the correct choice from the following options.
A) 12
B) 13
C) 15
D) 18
E) 22

Rationale: "x = - 2 and y = - 4 x - y = - 2 - ( - 4 ) = - 2 + 4 = 2 x * y = - 2 * - 4 = 8 now we apply it in the equation 5 ( x - y ) ^ 2 - xy = 5 ( 2 ) ^ 2 - 8 = = > 5 * 4 - 8 = 20 - 8 = 12 answer : a"
Answer: A