x÷2+y=27 x÷2+2y=44 一步一步的解开

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 当x+y=2时7(x+y)一(x+y)+(x+y)=? 化简求值:[(3x一2分之1y)^2+3y(x一12分之y)]÷[(2x+y)^2一4y(x+4分之1y)],其中x=2,y=一1. 已知x+y=一1求[(x一2y)^2+(x一2y)(x+2y)一2x(2x一y)]÷2x的值 [(2x-y)(2x+y)+y(y-6x)]÷2x=? 2x-y=2,求[(x²+y²)-(x-y)²+2y(x-y)]÷4y 先化简,再求值:y(x-y)-x(x+y)/x²-y²÷x²+y²/x+y,其中x=2,y=-1 1-[(x-y)/(x+2y)]÷[(x+y)(x-y)/(x+2y)²] 1-[(x-y)/(x+2y)]÷[(x+y)(x-y)/(x+2y)²]= 一、 (x-y)^5÷(y-x)^2-(x-y) 二、 先化简,后求值 (2x-y)^13-[(2x-y)^3]-[(y-2x)^2]^4 其中x=2 y=-1 x²-4y² x+2y---------- ÷ --------分数线x²+2xy+y² x²+xyx²-4y² x+2y----------÷--------分数线x²+2xy+y² x²+xy(x+2y)(x-2y)x(x+y)=----------------(x+y)(x+y)(x+2y)(x-y)x=------(x+y)这样对了吗? 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013先化简。在求值 【（x+2y)（x-2Y)-(x-2y)²】÷4Y,其中x=2,y=½ 【（x+y)²-（x+y）（x-y)】÷2y其中x=-2011y=2012 (x+y)(x-y)+(x-y)^2-(6x^2×y÷2y-2xy^2÷2y)其中x=-3,y=1/3 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 先化简,再求值[(2x+y)^2-(2x+y)(2x-y)-y(5x+y)]÷(1/2y),其中x-y=2 化简求值:[(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y,其中x=二分之一,y=2