this is what you need to do.
1. set up the truth tables using the following a, b, c, a not,
b not, result.
2. write down a, b, c.
3. then write down the opposit values for a not, b not in the
table.
4. solve your logic using the anot, b, c logic.
5. this has always helped me in the past.
regards,
james.