已知X+Y=3,xy=1 ,(1)求X2+Y2的值 (2)求X-Y的值
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x+y=4,xy=3求(1)x2=y2 (2)x-y的值
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值.
已知实数x,y满足(x2)+(y2)-xy+2x-y+1=0,求x,y的值
已知实数x、y满足X2+y2-xy+2x-y+1=0,试求x、y的值
已知x2+y2=20,x2+xy-2y2=2(x+2y),求x+y的值
x(x-1)-(x2-y)=-3,求x2-y2-2xy的值
已知X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
已知x+y=4,xy=2,求x2+y2+3xy的值.