### Home > A2C > Chapter 5 > Lesson 5.2.1 > Problem 5-70

5-70.

Consider the arithmetic sequence 2, *a* − *b*, *a* + *b*, −35, … Find *a* and *b*. Homework Help ✎

Since this sequence is arithmetic, what has to be true about the differences between terms?

How many times would you add the difference to get from 2 to 35?

2 + *d* + *d* + *d* = 35

*d* = 11

Since you know the first term and the common difference, you can write all four terms of the sequence.

Use the sequence to write a system of equations: *a* − *b* = ? and *a* + *b* = ?

*a* = 18.5, *b* = 5.5