（3x-2y-1)×多少=1-（3x-2y)的平方

已知1/x-1/y=3,则代数式x(2-7y)-y(7x+2)/x(1-y)-y(x+1)的值为多少. 已知x+y+2(-x-y+1)=3(1-y-x)-4(y+x-1),则x+y等于多少 （x+3y）（3y-1）=9y^2+x等于多少? 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 x[x-1]-[x^2-y]=2,3x^2加3y^2/2-3xy等于多少 若1/x+1/y=3,4y-2xy-4x/3x+xy-3x等于多少 (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y (x-y)^2+(x+y)(x-y) 其中 X =3 Y=-1 已知1/X+1/Y=6,则3X-2XY+3y/3XY+X+Y=多少 1/x-1/y=3 求x-3xy-y/2x-xy-2y 等于多少 已知2X-y=3,那么1-4X+y-2X+2y的值为多少, 若2^x=4^y+1,27^y=3^x-1,则X-Y的值为多少? 若2x-3y= -10,且x,y互为相反数,则(x+1(y-3)得多少?