x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
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
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
{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
2(x+y) 3x+3y=24 x+y/2x x y/2y= 1
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
9y=3x-(x-1),4(x+y)-(2x+4)=8y
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=