x,+y=5 xy=3 求xx+yy
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
知x/3=y/4=z/5,求(xy+yz+xz)/xx+yy+zz
x+y+z=5,xx+yy+zz=6,求xy-xz-yz的解
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xx+yy+4x-6y+13=0,求(xx-2x)/xx+3yy的值.
已知x-y=5,y-z=4,求xx+yy+zz-xy-yz-xz的值
已知(x+y)(x+y)=25,(x-y)(x-y)=9求xy与xx+yy的值
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,x/3 = y/1 = z/2 ,求 2xx - 2yy + 5zz /xy + yz +zx 的值.(/表示分数
若x/3=y/4=z/5,则(xy+yz=xz)/(xx+yy+zz)的值为