y=2x-1/x^2+2x+2和y=x-2/x^2-3x+2的值域

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (x-2y)(x+y)-2x(-2x-3y)+6x(-x-y),其中x=-1,y=2要讲解和答题 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=2 （x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3. x+2y=2x+y+1=7x-y 求：2x-y? 方程组2x-(x+y)=-1和x+4(x+y)=22 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 方程x(x*x+y*y-1)=0和x*x-(x*x+y*y-1)^2=0表示的图形是? y=(2x)/x-1化简成用y表示x 设x,y满足约束条件x+y>=1,x-y>=-1,2x-y 设x,y满足约束条件x+y>=1,x-y>=-1,2x-y 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 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1