17. 解:原式=
=1
16. 解:原式
.
15.
原式=4-1+1+3
=5
14. 解:
13. 解:
12. 原式
11. 解:原式····························································································· 3分
6分
10. 解:原式
9. 解:原式································ (4分)
8. 解:原式=
==2