设x+y=1,x2+y2=2,求x7+y7的值.
已知:点(x,y)在直线y=-x+1上,且x2+y2=2,求x7+y7的值.
已知x+y=4 xy=1,求x2+y2,x3+y3,x4+y4,x5+y5 x6+y6 x7+y7
点P1(x1,y1),P2(x2,y2),……P7(X7,Y7)在函数y=16/x的图像上,△P1OA1,△P2A1A2
设x,y为实数,且x2+xy+y2=1,求x2-xy+y2的值的范围
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知2x+y=7,x2+y2=5,求(4x+2y)2-3x2-y2+2(1-y2)的值.
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
设x、y为实数,且x2+xy+y2=3,求x2-xy+y2的最大值和最小值.
设正实数x,y满足x2-xy+y2=1,求x2-y2的最大值和最小值
2010.09.已知x、y为实数,且(x2+y2)(x2+y2+1)=20,求x2+y2的值
已知x,y为实数,且(x2 +y2)(x2 +y2+2)=3.求x2 +y2的值