若xx+yy=2,x+y=1则xy=?
已知2x=3y,求xy/xx+yy-yy/xx-yy的值
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+xy=1,xy-yy=-4,则xx+2xy-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,
已知x=1/2 y=1/3 z=1/4 则(xx+yy-zz+2xy)/(xx-yy+zz-2xz) 得多少?
(x-y)(x+y)(xx-yy)=?
已知XX+YY=7 XY=-2 X= Y=?
X-Y=4,xy=12则xx+YY的值
若x/3=y/4=z/5,则(xy+yz=xz)/(xx+yy+zz)的值为
如果实数X,Y满足XX+YY=1,求(1+XY)(1-XY)的最大值和最小值
已知:xx-xy=7,xy-yy=4,则xx-yy=( )