x-y=3,(x+y)(x+y)=25,求xy/xx+yy的值?
已知2x=3y,求xy/xx+yy-yy/xx-yy的值
已知(x+y)(x+y)=25,(x-y)(x-y)=9求xy与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+yy+4x-6y+13=0,求(xx-2x)/xx+3yy的值.
(x-y)(x+y)(xx-yy)=?
已知x-y=5,y-z=4,求xx+yy+zz-xy-yz-xz的值
已知 xx-2x+yy+6y+10=0 求x+y的值
x+y+z=5,xx+yy+zz=6,求xy-xz-yz的解
知x/3=y/4=z/5,求(xy+yz+xz)/xx+yy+zz
设x=1/(√3-2),y=1/(√3+2)求代数式 (xx+xy+yy)/(x+y) 的值》
x,y为实数,且XX+YY/2+4≤XY+2Y求X,Y的值