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

[2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^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 [(x+2y)^2-(x-y)(x+2y)-5y^2]÷(2y) (x-2y)(x+2y)一(3x+y)(3x一y) 计算[(x+2y)²-(x+y)(x-y)-5y²]÷(2x) 化简(2x/(x+y)一4x/(y-x))÷8x/(x^2-y^2) (一2x^3y^3)^2(-3x^2y)^3÷(-1/2x^5y^4) 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y [(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y 计算(一x一y)(x一y)+(x+y) 当x+y=2时7(x+y)一(x+y)+(x+y)=? 2x一5y=一3 一4x十y=一3 [(x-2y)(x+2y)+4(x-y)^2]÷5y 化简求值（2X十y）（X一2y）一2x（X十y）其中x,y满足X＾2十y＾2一2X十4y＝一5 把(x十y)和(x一y)2各看成一项合并一3(x一y)2一7(x十y)十5(x一y)2十9(x十y)中的同类项 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+5y）（x+4y）-（x-y）（x+y）,其中x=一又2/5,y=-1/7