### Home > GB8I > Chapter 11 Unit 12 > Lesson INT1: 11.1.1 > Problem 11-12

11-12.

An arithmetic sequence has . Write an equation for the sequence. What is

*?*

The general equation for an arithmetic sequence is .

Use to write an equation.

Use

Solve the system of equations you wrote for and

*.*

To find , substitute

*in the equation that you wrote.*