To Find: AP and its 30th term (i.e. a30=?)
Given: a5 = 5 and a13 = –3
Formula Used: an = a + (n – 1)d
(Where a=a1 is first term, a2 is second term, an is nth term and d is common difference of given AP)
By using the above formula, we have
a5 = 5 = a + (5 – 1)d , and a13 = –3 = a + (13 – 1)d
a + 4d =5 and a + 12d = –3
On solving above 2 equation, we and a + 12d = –3get
a = 9 and d= (–1)
So a30 = 9 + 29(–1) = –20
AP is (9,8,7,6,5,4……) and 30th term = –20