当x2+2y2=1时,求2x+3y2的最值.
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
已知2x+y=7,x2+y2=5,求(4x+2y)2-3x2-y2+2(1-y2)的值.
已知(x2+y2+3)(x2+y2-2)-6=0,求x2+y2的值
已知3x2+2y2=6x,试求x2+y2的最大值.
已知实数x,y满足x2+y2-2x+2y=6求x2+y2的最值
已知x,y为实数,且(x2 +y2)(x2 +y2+2)=3.求x2 +y2的值
已知实数x,y满足方程x2+y2-4x+1=0求x2+y2+2x的最值
当x=2,y=1 求{(x2+y2)/(x2-2xy+y2)+(2)/xy÷[(1/x)-(1/y)]}÷(x+y)的值
x(x-1)-(x2-y)=-3,求x2-y2-2xy的值
x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值