Question

-4(x+3y)^3 +(x-3y).(x+y)(x-y)-(2x-y)^3

Answer 1

\(=-4\left(x^3+9x^2y+27xy^2+27y^3\right)+\left(x-3y\right)\left(x^2-y^2\right)-\left(8x^3-12x^2y+6xy^2-y^3\right)\)

\(=-4x^3-36x^2y-108xy^2-108y^3+x^3-xy^2-3x^2y+3y^3-\left(8x^3-12x^2y+6xy^2-y^3\right)\)

\(=-3x^3-39x^2y-109xy^2-105y^3-8x^3+12x^2y-6xy^2+y^3\)

\(=-11x^3-27x^2y-115xy^2-104y^3\)