If (x+y)3 - (x-y)3 - 3y(2x2-3y2) = ky3, then find the value of k.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 11
(x+y)3 - (x-y)3 - 3y(2x2-3y2) = ky3
⇒ x3 + y3 + 3xy2 + 3x2y - x3 + y3 + 3x2y - 3xy2 - 6x2y + 9y3 = ky3
⇒ 11y3 = ky3
Thus, k =11