某商品销售量y(件)与销售价格x(元/件)负相关,则可能作为其回归方程是( )
A:y∧=-10x+200
B:y∧=10x+200
C:y∧=-10x-200
D:y∧=10x-200
如图,有以下列判断:①∠1与∠3是内错角;②∠2与∠3是内错角;③∠2与∠4是同旁内角;④∠2与∠3时同位角.其中,正确的说法有( )
用一种正多边形铺满地面,不能铺满的是( )
22+5=____
30+40=____
18-6=____
31+6=____
23-6=____
---- Would you like some more soup?---- _______. It is delicious, but I've had enough.