Question

In an AP if the common difference (d)=-6 and the seventh term (a7) is 4 then find the first term.​

Answer 1

Step-by-step explanation:

Given-

(i) d = -6

(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(-6)

=> 4 = a + (-36)

=> 4 = a - 36

=> a = 4 + 36

=> a = 40

Hence-

First term of AP is 40.