Question

(а+б)^2(а-б)-2аб(б-а)-6аб(а-б)=(а-б)^3

Answer 1

(a^2+2ab+b^2)(a-b)+4ab^2-4a^2=(a-b)(a^2+2ab+b^2)
4ab^2=4a^2b
ab^2=a^2b
a=b