# Given an arithmetic sequence with a_23=- 372 and a common difference of d=-8, how do you find the value of a?

Mar 31, 2017

$- 196$

#### Explanation:

${a}_{n} = {a}_{1} + \left(n - 1\right) d$

${a}_{23} = {a}_{1} + \left(23 - 1\right) d$

$- 372 = {a}_{1} + \left(22\right) \left(- 8\right)$

$- 372 = {a}_{1} - 176$

$- 372 + 176 = {a}_{1}$

$- 196 = {a}_{1}$