2x+4y=x+5y+5这是1式 3x+y=2+4y这是2式 求x.y
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x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
设x,y是有理数,并且x,y满足x^2+2x+y^2-4y+5=0求x+y的值
已知4x=9y求(1)x+y/y (2)y-x/2x
若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*
已知x²+y²+5=2x+4y,求代数式(2x²-(x+y)(x-y))x((x+y-1)
1/(x+y)-1/(x+y)=3/20 2/(x+y)+3/(x-y)=19/20 这是
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
求5x-2y=x-y=4x-3y-2的解