3a+3=3(a+1)______(判断正误)
由乘法分配律得,3(a+1)=3×a+3×1=3a+3,
则3a+3=3(a+1).
故答案为:正确.
How does he go to work? [ ]
A. By bus.
B. At seven o'clock.
较大儿童或成人脑积水行分流术时,应选择怎样的分流管()
A.低压分流管
B.中压分流管
C.高压分流管
D.低、中压分流管都可以
E.中、高压分流管都可以