Question

Find the 13th term of the arithmetic sequence whose common difference is d=7 and whose first term is (see photo attached)

Answer 1

Explanation:

The formula for an arithmetic sequence is

`a_(n)=a_(1)+d(n-1)`

where n is the position of the number you are looking for, a₁ is the first number in the sequence, and d is the common difference. We are given the following information:

n = 13,

a₁ = 5, and

d = 7

Filling in our formula then looks like this:

`a_(13)=5+7(13-1)` and

`a_(13)=5+7(12)` and

`a_(13)=5+84` so

the 13th term in our sequence is 89