Question

(Please Help!) The formula to find a certain number in an arithmetic sequence is an=a1+d(n−1) where an represents the nth term of the sequence, a1 is the first term of the sequence, and d is the common difference. Solve for d.

Answer 1

A

Explanation:

you move the a^1 to the left which becomes a^n-a^1. then you move (n-1) to the left as well which becomes a^n-a^1/n-1=d. you switch the places and tada, the answer.

Answer 2

The correct option is A)
`d=(a_n-a_1)/(n-1)`

Explanation:

Consider the provide equation.

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

We need to solve the equation for d.

Subtract
`a_1` from both sides

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

`a_n-a_1=d(n-1)`

Divide both sides by n-1.

`(a_n-a_1)/(n-1)=(d(n-1))/(n-1)`

`d=(a_n-a_1)/(n-1)`

Hence, the correct option is A)
`d=(a_n-a_1)/(n-1)`