Question

In an AP if the common difference (d)=-5 and the seventh term (a7) is 4 then find the first term.​

Answer 1

Step-by-step explanation:

Given-

(i) d = -5

(ii) a7 = 4

We know that nth term of AP is

=> an = a + (n - 1)d

=> a7 = a + (7 - 1)d [n=7]

=> 4 = a + 6(d)

=> 4 = a + 6(-5)

=> 4 = a + (-30)

=> 4 = a -30

=> a = 4 + 30

=> a = 34

Hence-

First term of AP is 34.