若x2+y2=10,xy=3,则(x-y)2=()
若x<y<0,则x2−2xy+y2+x2+2xy+y2=( )
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/xy的值
已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x2+y2-10x-6y+34=0,求(x-y/x+y)2÷x2-y2/xy×x2+2xy+y2/x2-xy 的值.
已知:x=3,y=-5,x2-2xy+y2/x2-y2的值是
已知x+y=4,xy=2,则x2+y2+3xy=______.
已知2x-3*根号(xy)-2y=0(x>0),则x2+4xy-16y2除以2x2+xy-9y2的值是多少?
已知x2-2xy=3y2且x,y为非零实数 求:(1)2x+y/x-2y (2)2x2-3y2+5xy/x2+xy+y2
先化简再求值:-(x2+y2)+[-3xy-(x2-y2)],其中x=-1,y=2.