若 X=1 Y=-1 与X=2 Y=2 是二元一次方程 AX+BY=4的解 求AB的值

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若x*x+y*y=x+y-1/2,求x,y的值如题 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若|y+1|与(x+2y-1)^2互为相反数,则x^y=? 一道二元二次方程组 x(x+y)=12 与 y(x-2y)=1 （x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3. 2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=2 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 y=2x*x+x-1与x轴y轴交点 x+2y=2x+y+1=7x-y 求：2x-y? 若变量x,y满足约束条件{x>=-1;y>=x;3x+2y 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 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 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