Question

刚刚忘记问了,X^3+y^3+3x^2Y-5Xy^2=(X-Y)(X^2+4XY-Y^2) 这步是怎么算出来的,有什么简

Answer 1

X^3+y^3+3x^2Y-5Xy^2

=x^3+4x^2y-xy^2-x^2y-4xy^2+y^3

=(x^3+4x^2y-xy^2)-(x^2y+4xy^2-y^3)

=X(X^2+4XY-Y^2)-y(X^2+4XY-Y^2)）

=(X-Y)(X^2+4XY-Y^2)

运用分组分解法