Simplify the following expression. $(2x - 3y)^3 - 18 xy (2x - 3y)$
Answer & explanation
Correct answer: option 2
We have to solve $(2x - 3y)^3 - 18 xy (2x - 3y)$
Put x = y = 1, ( These value will satisfy the given equations)
Value of the expression = (2 × 1 - 3 × 1)3 - 18(2 × 1 - 3 × 1)
= -1 - 18(-1)
= -1 + 18 = 17
If we check option (2),
8(1) - 72(1) + 108(1) - 27(1)
= 116 - 99 = 17
So the answer is = $8x^3 - 72x^2y + 108 xy^2- 27 y^3$