已知xx+yy=7,xy=-2,求多项式5xx-3xy-4yy-11xy-7xx+2yy的值.
已知2x=3y,求xy/xx+yy-yy/xx-yy的值
已知xx+xy=1,xy-yy=-4,则xx+2xy-yy=
已知:xx-xy=7,xy-yy=4,则xx-yy=( )
已知x(x+1)-(xx+y)=3,求(xx+yy)/2-xy的值
x(x+1)-(xx+y)=-3,求(xx+yy)/2-xy的值
已知(XX+YY—2)(XX+YY)=3,求XX+YY
已知x,y是实数,且适合方程(xx+xy-12)(xx+xy-12)+(xy-2yy-1)(xy-2yy-1)=0求x,
3xx+xy+yy=15
已知xx+yy+4x-6y+13=0,求(xx-2x)/xx+3yy的值.
已知XX+YY=7 XY=-2 X= Y=?
已知x=1/2 y=1/3 z=1/4 则(xx+yy-zz+2xy)/(xx-yy+zz-2xz) 得多少?
已知x-y=5,y-z=4,求xx+yy+zz-xy-yz-xz的值