### Home > A2C > Chapter 2 > Lesson 2.1.7 > Problem 2-104

2-104.

An arithmetic sequence has and

*. What is*

*?*

The general equation for an aritmetic sequence is

Use to write an equation.

*or*

Use to write another equation.

Solve the system of equations you wrote for and

*.*

To find , substitute

*in the equation that you wrote.*