1.(2/x+y) - (1/x-y) = 2.当x=1984 y=1916时 :(x^4-y^4/x^2-2xy+y^2) × (y - x/x^2+y^2) =

[(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y 感激不尽1.x,y满足(x-y-1)(x+y) 1、y-x/x²-y²2、(x-y)(y-z)(z-x)/(z-y)(y-x)(x-z) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 1.(x-2y)(x+2y)-(x平方+y)(x平方-y) 2.(2x-y)(y+2x)-(2y+x)(2y-x)3.已知：x+y=6,x平方-y平方=48,求x,y的值4.x平方-2x分之x+2 -- x平方-4x+4分之x-1 (x-y)(2x-y-1) 1.(x-y)(x+y)+(x-y)+(x+y)2.x(x+2)-(x+1)(x-1),其中x=-二分之一请写清步骤,结果. [(x/x-y) -1]/(y的平方/x+y)乘以(x-x的平方/x+y),其中x=—2,y=—1. (x/x+y-x/y-x-2xy/x.x-y.y)/(1/x-1/y) 分式化简 计算：1.（x-1)^2+2(1-x) 2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-2y/(x+y）1.（x-1)^2+2(1-x)2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-2y/(x+y） x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 化简y(x+y)+(x+y)(x-y)-x^2 2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=2 （x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3. 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 1.计算(a^2+a+1)(a^2-a+1) 2.计算(x-y)(x+y)+(3x-2y)(2x+y)-x(6x-y)