(1){5x-3y=5 6x+2y=6 (2){3x+2y=5x+2 2(3x+2y)=2x+8(3){x+3/3+y+
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
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
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
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:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1