The 7^th and 21^st terms of an AP are 6 and -22 respectively. Find the 26^th term.

Explanation:-

7^th term = 6;
21^st term = -22;
That means, 14 times common difference or -28 is added to 6 to get -22;
Thus, d = -2;
7^st term = 6 = a+6d;
Or, a+(6*-2) = 6;
Or, a = 18;
26^st term = a+25d = 18-25*2 = -32.