All the kids had a lot of fun Children's Day. They sang and danced happily all day.
A:in
B:at
C:of
D:on
两圆x2+y2-4x+6y=0和x2+y2-6x=0的连心线方程为( )
小明不慎将墨水滴在数轴上,根据图中的数值,判定墨迹盖住部分的整数的和是____ .