一道数学化简题 3y^2+4y-7/(3y^3-3y)+(7y^2-7)

（2y-3)(-y+4)=(y-2)(y-5)-3y(y-7/3)解方程 10y+2(7y-2)=5(4y+3)+3y怎么算 解不等式：5y(8-y)-3y(5-3y)+2y(7-2y)>-39 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 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 数学(x-y)^5*(y-x)^3*(x-y)^2 (-3x+7y)(-7y-3x)-(x-3y)(2x+3y) {2x+y/3-2y=0 2(2x+y)-5=7y 2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方 y-7-8y=2y-3-5y 咋写? 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于