(1)y=x,y+4x=15; (2)x+2x-3y=1; (3)x-7y=0,x-9y=8=0.
9y=3x-(x-1),4(x+y)-(2x+4)=8y
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
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
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
已知4x=9y求(1)x+y/y (2)y-x/2x
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)+...-(
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
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