21st Term Of Ap Whose First Two Terms Are 3 And 4 Is

The 21st term of an AP whose first two terms are – 3 and 4, is (a) 17 (b) 137 … (c) 143 …

Answers:

(b) Given, first two terms of an AP are a = – 3 and a + d = 4.
⇒  – 3 + d = 4