4x^1/4(-3x^1/4y^1/3)/（-6x^-1/2y-2/3）

{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 （x+2)(x+3) (x-4)(x+1) (y+4)(y-2) (y-5)(y-3) 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 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 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 ｛4/(x+y)+6/(x-y)=3 ｛9/(x-y)-1/(x+y)=1 9y=3x-(x-1),4(x+y)-(2x+4)=8y 化简求值:(x+y)-(2x+1/2y)-(3x+1/6y)-(4x+1/12y)-(5x+1/20y)-.(10x+1 计算(4x^2-2x^3+6x)/(-2x)-(x-1)^2y^2-4/y^2-y-6)+(y+2/y-3)/(y+1/ 3分之2(X-Y)-4分之X+Y=-1,6(X+Y)-4(2X-Y)=16 解方程组：2(x-y)/3-x+y/4=-1 ,6(x+y)-4(2x-y)=16