与-3ab是同类项的是( )
A:a2b
B:-3ab2
C:12ab
D:a2b2
⑴Are you a teacher? ____ A.No. I am Bill.
⑵Are you hungry?____ B.This is a cat.
⑶Is it a bag?____ C.No. I am not hungry.
⑷Are you Mike?____ D.Yes, it is.
⑸What is this?____ E.Yes, I am.
以下说法正确的是( )
句型转换。
设变量x,y满足约束条件x+2y-5≤0x-y-2≤0x≥0,则目标函数z=2x+3y+1的最大值为( )