(-xy-2z²)(-xy+2z²)-(xy)² Упростить выражение

Question

(-xy-2z²)(-xy+2z²)-(xy)² Упростить выражение

Answer 1

(-xy-2z²)(-xy+2z²)-(xy)² =-(xy+2z²)(-xy+2z²)-(xy)²=-(4z⁴-x²y²)-x²y²=
=-4z⁴+x²y²-x²y²=-4z⁴

Answer 2

(-ху-2z²)(-xy+2z²)-(xy)²=
=(-xy)²-2xyz²+2xyz²-(xy)²=x²y²-x²y²=0