An |
Bn |
7n+1 |
4n+27 |
a11 |
b11 |
A.
| B.
| C.
| D.
|
(a1+a21)×21 |
2 |
(b1+b21)×21 |
2 |
An |
Bn |
7n+1 |
4n+27 |
a11 |
b11 |
21a11 |
21b11 |
A21 |
B21 |
7×21+1 |
4×21+27 |
4 |
3 |
A.-
| B.-
| C.
| D.
|
A.1 | B.-1 | C.2 | D.-2 |
A.5 | B.10 | C.15 | D.20 |
A.2个 | B.3个 | C.4个 | D.5个 |
a2-a1 |
b3-b2 |
© 2017-2019 超级试练试题库,All Rights Reserved.