Question

In an AP if the common difference (d)=-7 and the seventh term (a7) is 4 then find the first term.​

Answer 1

Answer:

46

Explanation:

Given-

(i) d = -7

(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(-7)

=> 4 = a + (-42)

=> 4 = a - 42

=> a = 4 + 42

=> a = 46

Hence-

First term of AP is 46.

Answer 2

Answer:

$given \\ d = - 7 \\ a7 = 4 \\ a7 = a + 6d \\ a + 6( - 7) = 4 \\ a - 42 = 4 \\ a = 4 + 42 = 46$

therefore, it's first term is 46