5X+6Y=500,4X+1Y=5Y+1X,X>Y,X=?,Y=?
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
3x+2y/4=2x+y/5=x-y+1/6
x+y=5; x^y+y^x=17
已知x²+y²+5=2x+4y,求代数式(2x²-(x+y)(x-y))x((x+y-1)
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
分式的加减:[(x/y-y/x)除以(x+y)+x(1/y-1/x)]除以1+x/y,其中x=5,y=2
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5