(3x 7y)^2-(3x-7y)^2
(-3x+7y)(-7y-3x)-(x-3y)(2x+3y)
2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
计算:(x-y)^7÷(y-x)^6+(-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)
x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8
1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y)
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
先化简再求值{(x-y)(x+y)-(x+y)(x-2y)}/y 其中xy的值是代数式{(3x-2y-7)^2+|2x+
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
[(3x+y)(x-y)-(2x+3y)(x-y)]*(x-y)
化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方