已知 (4x-2y-1)^2+根号xy-2=0,求2x^2y-4x^2y62-xy^2的值 注:^2为二次方

问题描述:

已知 (4x-2y-1)^2+根号xy-2=0,求2x^2y-4x^2y62-xy^2的值 注:^2为二次方

(4x-2y-1)^2+根号xy-2=0,
所以有:
4x-2y-1=0
xy-2=0
解得:2x-y=1/2 ,xy=2
2x^2y-4x^2y2-xy^2
=xy(2x-4xy-y)
=2(1/2-4*2)
=1-16
=-15