24.若实数x,y满足：x^2+y^2-2x+4y=0,求x-2y的最大值.24.若实数x,y满足：x^2+y^2-2x+4y=0,求x-2y的最大值

若实数x,y满足x^2-xy-y^2 =0,则x/y=? 若正实数x.y满足x+y=xy,则x+2y的最小值 若实数x,y满足不等式组x>=0 ,y>=0,x+2y 已知实数x,y满足y=|x-1|若x+2y 已知实数X,Y满足2 已知实数xy满足x+2y 已知实数xy满足 x+y-2 已知实数x.y满足(x+2)^2+y^2( 若实数x,y满足y 若实数x,y满足不等式y 若实数x,y满足x²+y²-2x+4y=0,求x-y的最大值 若实数x y满足（x+y)²+（x+y)-2=0则x+y值为 若实数x,y满足约束条件x-y-2=0,2y-3 若实数x,y满足x 若实数x,y满足x 设实数x,y满足 x>=0 x-2y>=0 x-y-2 设实数x,y满足约束条件：x>=2;y>=x;2x+y 当实数x,y,满足约束条件{x>0 y>=x 2x+y+k