y=-1/3x,y=2x,y=7/2x,y=-5x的图像哪个最靠近Y轴,有什么规律?

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 x+2y=2x+y+1=7x-y 求：2x-y? (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 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 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x+y)(2x-3y)=?