(a) The 3rd and 19th terms of an A.P. are 13 and 77 respectively. Find the A.P.
(b) The 5th and 8th terms of an A.P. are 56 and 95 respectively. Find the 25th term of this A.P.
(c) The pth and qth terms of an A.P. are q and p respectively. Prove that its (p + q)th term will be zero.