已知:x+y=-3,xy=-0.5,求:(1)x2+y2;(2)(x-y)2
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
已知x2-2xy=3y2且x,y为非零实数 求:(1)2x+y/x-2y (2)2x2-3y2+5xy/x2+xy+y2
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X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知x2+y2=5,xy=2,求1/(1/x+1/y)
已知x2+y2-10x-6y+34=0,求(x-y/x+y)2÷x2-y2/xy×x2+2xy+y2/x2-xy 的值.
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x+y=5,xy=4,求:(1)(x+y)2;(2)x2+y2;(3)x-y的值.