Question

In an AP with 18 terms the common difference is $-3$−3 . If the nth term is $-5$−5, what is its first term?

Answer 1

46

Explanation:

The n th term of an AP is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here d = - 3 and
`a_(18)` = - 5 , thus

a₁ + (17 × - 3) = - 5

a₁ - 51 = - 5 ( add 51 to both sides )

a₁ = 46

Answer 2

a = 46

Explanation:

Refer to the attachment.