X+4Y=14 X-3/4+Y-3/3=1/12
{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
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)+...-(
[(2x+y)^2+(y+2x)(y-2x)-2y(4x-y)]/4y,其中x=1/2,y=1/3
先化简,再求值:[(x+y)(x-y)-(x-y)^2+2y(x-3y)]/(-4y),其中x=1,y=-2
9y=3x-(x-1),4(x+y)-(2x+4)=8y
已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y除以2x-y
已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值
(5x+3y)(3y-5x)-(4x-y)(4y+x)=
若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值?