Question

因式分解：x的二次方-4xy+4y的二次方-3x+6y

Answer 1

第一题：(x-2y)*x^3-(y-2x)*y^3=x^4-2x^3y-y^4+2xy^3=(x^4-y^4)-2xy(x^2-y^2)=(x^2+y^2-2xy)(x^2-y^2)

=(x-y)^2*(x+y)*(x-y)=(x-y)^3*(x+y)

第二题看不懂……