Question

分式x+y分之x-y与（x+y）²分之x²-y²相等吗?

Answer 1

相等.理由如下;

∵(x-y)/(x+y)

∴x+y≠0

∴(x-y)/(x+y)=[(x-y)(x+y)]/[(x+y)(x+y)]=(x²-y²)/(x+y)²