2x-{7y+[4x-7y-(2x-6x-4y)-3x]}简便算

若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 将(x-y)看成一个整体,将3(x-y)²-4(x-y)+7(x-y)-6(y-x)²-2(y-x)合并同类项. 3(x-y)^2-7(x-y)+8(y-x)^2+6(y-x)合并同类项. 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 计算：(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2 2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方 计算(x-y)^7÷(y-x)^6+9-x-y)^3÷(x+y)^2 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) -6x-y-7x+6x-2y-10x+8y+x+6x-8y的值 把(x+y),(x-y)个作为一个整体合并同类项1,7(x+y)-2(x+y)-4(x+y)+2(x+y)2,(x-y)²＋2(x-y)－(x-y)－2(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) 化简3(x-y)-7(x--y)+2(y-x) 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) (x-y)(x-2y)+(x-2y)(x-7y),其中X=4,Y=1.5 2x-{7y+[4x-7y-(2x-6x-4y)-3x]}简便算 把(x-y)看作一个整体,化简:(1)5(x-y)+2(x-y)-4(x-y);(2)3(x-y²-4(x-y)+7（x-y)-6(x-y)