2. These are essentially what Nos 22 (skip line 1 and make lines 2,3 the premises) and 23 amount to, from Ex 3.3.1. (Change A,B,C to p,q,r)
3. Exercise 4.3.1 #7. There is one solution in the text; HERE is another
4. The derivation for the first one also comes from Ex 3.3.1, although the tableau is simpler (for both). Here they are.
5. This one translates to No 2 from the sample tableau done in Chp 4, and the derivation is from Chp 3.