Question

What is the 15th term in the arithmetic sequence described by this explicit formula? an = 63 + (n – 1)(–7)

Answer 1

a15 = 63 + (15 - 1)(-7)
a15 = 63 + 14(-7)
a15 = 63 - 98
a15 = - 35 <=== ur 15th term

Answer 2

`a_(15)` = -35.

Explanation:

Given :
`a_(n)` = 63 + (n – 1)(–7)

To find : What is the 15th term in the arithmetic sequence .

Solution : We have given
`a_(n)` = 63 + (n – 1)(–7).

We need to find 15 th terms , n = 15

`a_(15)` = 63 + (15 – 1)(–7).

`a_(15)` = 63 + 14 (-7).

`a_(15)` = 63 -98.

`a_(15)` = -35.

Therefore,
`a_(15)` = -35.