Question

The formula for any arithmetic sequence is an = a1 + d(n - 1), where an represents the value of the nth term, a1 represents the value of the first term, d represents the common difference, and n represents the term number. What is the formula for the sequence -15, -11, -7, ...? an = -15 + (-4)(n - 1) an = -15 + (n - 1) an = 4 + (-15)(n - 1) an = -15 + 4(n - 1)

Answer 1

4th choice

Explanation:

First we would just solve the equation since that is the easiest way. So 15 would be our a1 or first term and each time the number is being added by 4 so we would get an = -15 + 4(n - 1) for our final answer or the 4th choice

Answer 2

option 4

Explanation:

-15, -11 , -7 ,......

First term =
`a_(1)` = -15

Common difference = d = 2nd term - 1st term

= -11 - [-15]

= -11 + 15 = 4

Plug in the values of
`a_(1)` & d in the formula

`a_(n) = a_(1) + d (n-1)\\\\a_(n) = -15 + 4*(n-1)`