来自董玉涛的问题
先化简,再求值:(xy-x)/x^2-2xy+y^2*x^2-y^2/x^2,其中:x=-2,y=1/2
先化简,再求值:(xy-x)/x^2-2xy+y^2*x^2-y^2/x^2,其中:x=-2,y=1/2
1回答
2020-10-03 01:02
先化简,再求值:(xy-x)/x^2-2xy+y^2*x^2-y^2/x^2,其中:x=-2,y=1/2
先化简,再求值:(xy-x)/x^2-2xy+y^2*x^2-y^2/x^2,其中:x=-2,y=1/2
(xy-x)/(x^2-2xy+y^2)*(x^2-y^2)/x^2
=x(y-x)/(x-y)^2*(x+y)(x-y)/x^2
=-(x+y)/x
=-(-2+1/2)/(-2)
=-3/4