1. (~a+b)(a+~b+c)~(a+b)
2. (a+~b)~(~a+b+c)(a+b)
3. (~a+b)(a+~b+c)~(a+b)
4. (~a+b)(~a+b+~c)~(a+b)
5. (a+~b)(a+~b+c)(a+b)
6. ~(~a+b)(a+~b+c)(a+b)
7. ab~c+ab~c+a~bc
8. a~b~c+ab~c+a~bc
9. ab~c+a~b~c+a~bc
10. ab~c+ab~c+a~bc
11. ab~c+~(ab)~c+a~bc
12. ac+ab~c+abc
13. ab~cb~c+a~bc
14. ab~c+ab~c+ac
15. ab~c+ac+a~bc