Question

先化简再求值，x分之x平方-y平方除（x-x分之2xy-y平方），其中x=2010，y=2011

Answer 1

解：(x²-y²)/x ÷ [x-(2xy-y²)/x]
=(x²-y²)/x ÷ [(x²-2xy+y²)/x]
=(x+y)(x-y) ÷ (x-y)²
=(x+y)/(x-y)
=(2010+2011)/(2010-2011)
= -4021

Answer 2

原式=[（x^2-y^2)/2]/[x-(2xy-y^2)/2]是这个吧？
如果是这个的话，原式=[(x^2-y^2)/x]/[(x^2-2xy+y^2)/x]
=(x^2-y^2)/(x^2-2xy+y^2)
=[(x+y)(x-y)]/[(x-y)^2]
=(x+y)/(x-y)
将x=2010,y=2011带入原式，原式=-4021