计算(8x-7y)(7y+8x)-(7x+8y)(7x-8y)

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 (x-y)^2+7(x+y)-11(x-y)^2-8(x+y),先化简.再求值 (3x-4y)(5x-4y)-(7x-8y)(6y-5x) x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8 因式分解:8(x-2y)-x(7x+y)+xy. -6x-y-7x+6x-2y-10x+8y+x+6x-8y的值 3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算 -8(2x-y)-{7x-[6x+2y-(10x-8y)]} 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 计算 （3X-5Y)+(-3X+Y) 7X-「-2X-(8X-1)」 2x-y=7,3x+y=8