如果x+y=-1,x-y=-3,那么x2-y2=______.
如果x+y=-1,x-y=-3,那么x2-y2=______.
若实数x,y满足3x2+2y2=6x,则x2+y2的最大值为______.
已知x2+4x+y2-2y+5=0,则x2+y2=______.
已知两圆x2+y2=1和x2+y2-6x-8y+9=0,那么这两个圆的位置关系是______.
如果实数x,y满足方程(x-2)2+y2=3那么x2+y2的最大值是 最小值是 y/x的最大值是 最小值是
x2-y2=55,x-y=5,则x+y=______.
如果x+y=0,xy=-7,x2y+xy2=______,x2+y2=______.
x2-x-y2-y 解法:=(x2-y2)-(x+y) =(x+y)(x-y)-(x+y) =(x+y)(x-y-1)
已知实数x、y满足(x2+y2)(x2+y2-1)=2,则x2+y2的值为______.
两圆x2+y2-4x+2y+1=0与x2+y2+4x-4y-1=0的公切线有______条.
若(x+y)2=25,(x-y)2=1,x2+y2的值是______.
已知实数x,y满足x+y=1,则x2+y2的最小值是______.