（-7x^2-8y^2）*(-x^2+3y^2) (3x-2y)(y-3x)-(2x-y)(3x+y)

（-7x^2-8y^2）*(-x^2+3y^2) (3x-2y)(y-3x)-(2x-y)(3x+y) 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 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) 2(x-y)+3（x+y）2-5(x-y)-8（x+y）2-（x-y） 化简3(x-y)-7(x--y)+2(y-x) 2（x-y）²-3(x-y)(-y-x) 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) (2x+y)²+(x+3y)(x-3y)-x(5x+8y)因式分解 -2x(3x-7y)+(x-y)(x^2+xy+y^2） 计算 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) x(x-y)2-(y-x)3 1.（（y+2x)(-2x+y)+4(x+2y)^2)/3y 2.（2(x-y)^3-8(x-y）^2(x+y)+6y(x-y)^2）/2（x-y)^2 1.(x^3-x^2-4x+1)/(x^2-3x+2)-(x^3-2x^2-9x+21)/（x^2-5x+6）+（x^2-3x+8）/（x^2-4x+3）2.{(x^2)/（x-y)}*{y/(x+y)}-{(x^4y)/(x^4-y^4)}÷{（x^2/x^2+y^2）^2} -(5x+y)-7(x-y) -2分之1（x+y）+4分之1（x+2y） 4x-2（x-2） -2x-（3x-1） x-(5x-2y)+2(2x-y) 25（x-2y)平方-4(y-2x)平方答案是3(3x-4y)(x-8y)还是21(x-2y)2还是（7x-6y）有（3x-14y) [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x