已知x2+xy=5,xy+y2=-1,则x2-y2=______.
已知x2+xy=5,xy+y2=-1,则x2-y2=______.
已知x2+xy=3,xy+y2=-2,则2x2-xy-3y2=______.
如果x2+xy=2,xy+y2=-1,则x2-y2=______,x2+2xy+y2=______.
已知x2+xy=2,y2+xy=5,则12x2+xy+12y2=___.
已知x+y=4,xy=2,则x2+y2+3xy=______.
因式分解:1-x2+4xy-4y2=______.
已知x2-xy=7,2xy+y2=4,则代数式x2+xy+y2的值是___.
已知x2-xy=3,xy-y2=-5,试求代数式x2+2xy-3y2的值.
已知x+y=5,xy=3 则x2+y2=______.
已知x+y=-5,xy=6,则x2+y2=______.
已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值
已知:x2+y2=7,xy=-2.求7x2-3xy-2y2-11xy-5x2+4y2的值.