会滴来、1.x+y/x-2+x-y/2-x=2.(1/a)÷（1/a+1)=3.已知分式2x-m/x+n,当x=2时,分式的值为0,当x=-1时,分式无意义,则m+n=4.-a^3/2c÷5a^2/-6cd5.y-3/4y-8÷（y+2-5/y-2)7.1+(a-1/1-a)÷(1+a/a^2-2a+1)8.（x/x-y-1)÷y^2/x+y×（x-x^2/x+y),其

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简y(x+y)+(x+y)(x-y)-x^2 因式分解x(x+y)(x-y)-x(x+y)^2 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) x^2(x-y)+(y-x) x(x-y)2-(y-x)3 1.（x+2)^2-(x+y)^32.(x-y)^2-(x-y)^33.(x-y)^2-(y-x)^3 计算:y-x分之x+y+x-y分之y-y-x分之2x-y 【(x-y)^2+(x+y)(x-y)】除以 2x [(x-y)²+(x+y)(x-y)]除以2x [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x [(x-y)^2-(x+2y)(x-2y)]/y 先化简 再求值(x-2y)(2y-x)+(2x+y)(2x-y )-(x-2y)(2x+y) 其中x=-2,y=-1. x^2-y分之y(x-y)-x(x+y)除以x+y分之x^2+y^2.其中x=2,y=-1.先化简再求值.