Simplify the following.
(x – 3y)3 + 27(y3 – xy2)
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. x3 – 9x2y.
(x – 3y)3 + 27(y3 – xy2)
⇒ x3 - (3y)3 - 3x2(3y) + 3x(3y)2 + 27y3 - 27xy2
⇒ x3 - 27y3 - 9x2y + 27xy2 + 27y3 - 27xy2
⇒ x3 - 9x2y