Question

If a_1=5a

Answer 1

Answer:

$a_5 = 21$

Step-by-step explanation:

Arithmetic sequence:

In an arithmetic sequence, the difference between consecutive terms is always the same, and this difference is called common difference.

The nth term of an arithmetic sequence is given by:

$a_n = a_1 + d(n-1)$

In which $a_1$ is the first term and d is the common difference.

In this question:

$a_1 = 5, d = 4$. So

$a_n = a_1 + d(n-1)$

$a_n = 5 + 4(n-1)$

Find the value of a_5

$a_n = 5 + 4(n-1)$

$a_5 = 5 + 4(5-1) = 5 + 16 = 21$

So

$a_5 = 21$