已知x2-y2=xy,且xy≠0,求代数式x2y-2+x-2y2的值.
问题描述:
已知x2-y2=xy,且xy≠0,求代数式x2y-2+x-2y2的值.
答
∵x2-y2=xy,
∴原式=
+x2 y2
=y2 x2
x4+y4
x2y2
=
(x2−y2)2+2x2y2
x2y2
=
3x2y2
x2y2
=3.