Question

Find the formula for the nth term of the arithmetic sequence -7, -4, -1 , 2

Answer 1

-7 + 3(n - 1)

Explanation:

(-4)-(-7) = -4 + 7 = 3

(-1)-(-4) = 3

2-(-1) = 3

then the common difference r = 3

and the first term is -7

since the nth term = first term + (n - 1)×r

then the nth term = -7 + (n - 1)×3

= -7 + 3(n - 1)