Q518
If x - y = 3, then what is the value of x3 - y3 - 9xy?
A.
3
B.
9
C.
18
D.
27
AnswerAnswer: Option D
Solution
Answer: Option D
Solution:
(x - y) = 3(x - y)3 = 27
⇒ x3 - y3 - 3xy(x - y) = 27
⇒ x3 - y3 - 9xy = 27