已知x2-y2=12,x-y=2,则x+y= ___ .
若x-y=2,x2-y2=10,则x+y= ___ .
已知x2+4x+y2-2y+5=0,则x2+y2=______.
已知实数x,y满足方程(x2+2x+3)(3y2+2y+1)=43,则x+y= ___ .
已知实数x,y满足x2+4xy+4y2-x-2y+14=0,则x+2y的值为 ___ .
已知正实数x,y满足x2+y2+xy=1,则x+y的最大值是___.
已知x+y=2,x-y=12,则分式2x2-2y2x2+2xy+y2的值是 ___ .
已知:(x+y)2=1,(x-y)2=17,则x2+y2=___,xy=___.
已知x2+y2=4,则2x+3y的取值范围 ⊙ ___ .
已知实数x,y 满足x2+y2+2x=0则x+y得最小值
已知实数x,y满足x2+y2-2x+4y=0,则x2+y2的最小值是
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知x-y=2,则x2-y2-4y=______.