如果2x-y=8,求代数式[(x^2+y^2)-(x-y)^2+2y(x-y)]除以(4y)的值.
问题描述:
如果2x-y=8,求代数式[(x^2+y^2)-(x-y)^2+2y(x-y)]除以(4y)的值.
答
((x^2+y^2)-(x-y)^2+2y(x-y))/(4y)=(x^2+y^2-x^2+2xy-y^2+2xy-2y^2)/(4y)
=(4xy-2y^2)/(4y)
=(2x-y)/2=8/2=4