3(x-y)^2-7(x-y)+8(y-x)^2+6(y-x)合并同类项.

18(x+y)^8(x-y)^7÷[3(x+y)^3(x-y)^3]^2 3(x-y)^2-7(x-y)+8(y-x)^2+6(y-x)合并同类项. 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) 计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8) 化简3(x-y)-7(x--y)+2(y-x) 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) [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 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= (2x+y)²+(x+3y)(x-3y)-x(5x+8y)因式分解 （-7x^2-8y^2）*(-x^2+3y^2) (3x-2y)(y-3x)-(2x-y)(3x+y) x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 已知实数x.y满足根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),求x,y 12y(x-y)^2-8(x-y)^3=? (-3x+7y)(-7y-3x)-(x-3y)(2x+3y) (x-y)^2+7(x+y)-11(x-y)^2-8(x+y),先化简.再求值 （x-y)^2+7(x+y)-11(x-y)^2-8(X+Y)的计算过程 (3x-4y)(5x-4y)-(7x-8y)(6y-5x) 4x-3y/x-2y÷6y-8x/y-2x