(x^2+y^2)/(x^2-y^2) 减去 (x+y)/(2x-2y) ,化简.
8个回答

你将分母漏了

(x^2+y^2)/(x^2-y^2) - (x+y)/(2x-2y)

= (x^2+y^2)/(x-y)(x+y) - (x+y)/2(x-y)

= 2(x^2+y^2)/2(x-y)(x+y) - (x+y)^2/2(x-y)(x+y)

= [2(x^2+y^2) - (x+y)^2]/2(x-y)(x+y)

= [2x^2+2y^2 - (x^2+y^2+2xy)]/2(x-y)(x+y)

= [2x^2+2y^2 - x^2-y^2-2xy]/2(x-y)(x+y)

= ( x^2+y^2-2xy)/2(x-y)(x+y)

= ( x-y)^2/2(x-y)(x+y)

= ( x-y)/2(x+y)