当x=-1,y=2时,求(4x^2-y^2)/4x^2-4xy+y^2/2x-y的值
问题描述:
当x=-1,y=2时,求(4x^2-y^2)/4x^2-4xy+y^2/2x-y的值
……加几个关键词?数学
答
(4x^2-y^2)/4x^2-4xy+y^2/2x-y
=1- y²/4x² -4xy+y²/2x -y
=1- 1 +8 -2 -2
=4