2. (4M and 1W) + (3M and 2W). Do the same sort of thing as above for each case.
3. (Number of possible committees that have the unwanted man) + (number of possible committes that don't have the unwanted man).
For the first case you're choosing 3 men from the 6 and 2 women from 3 (not 4). For the second case you're choosing 3 men from 5 (not 6) and 2 women from 4. For each case do the same sort of thing as was done in question 1.