设实数x,y满足4x^2+y^2=8,则xy的最大值等于___?设不等式|ax+b|5)的解集为(-1,4),求常数a,b的值

设实数x,y 满足x²+4y²+2x-4y+2+0 则x+y= 设实数x,y满足x^2+2xy+4y^2=1,则x+2y最大值 设实数X,Y满足X^2+Y^2=1,则3X+4Y的最大值为多少 设实数X,Y满足2X+Y-2>=0,X-2Y+4>=0,3X-Y 设正实数x,y满足x^3+y^3=x-y,求证：x^2+4y^2 设实数x,y满足2x+y≤4,x-y≥-1,x-2y≤2,则z=x+y的最大值为 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 设实数x和y满足约束条件,x+y≤10,x-y≤2,X≥4,则Z=2x+3y的最小值为? 设实数x,y满足x^2+4y^2+2x-4y+2=0,则x+y=? 设实数x,y满足x+y=4,则根号x^2+y^2-2x+2y+2（这几个一起开根号）的最小值 设实数x、y满足x²+y²+4x-2y-4=0 则x²+y²的最大值是求详细过程、谢谢~ 设实数x,y满足（x-1）^2+(y+2)^2=5,则x-2y的最大值 设实数x,y满足方程组①x-y-2=0 ③2y-3 设实数x,y满足x^2+4y^2+2x-47+2=0,则x^2y+2x的值等于_________ 设Z=x+y,其中实数x,y满足不等式x+2y>=0,x-y 设z=x+y,其中实数x,y满足{x+2y>=0,x-y 设实数x,y满足x²+1/2y²4-xy+2y=0.则x=___,y=___