### Home > GB8I > Chapter cc46 > Lesson cc46.1.2 > Problem 6-18

6-18.

What is the missing term in each sequence? Homework Help ✎

a.

Hint: This is an arithmetic sequence.b.

Review the Math Notes box in section 5.3.2

Note that there are terms missing in the table.

*a*_{1} = 1 while *a*_{5} = −7.

What is the common difference?

Review the Math Notes box in section 5.3.2

Is this Arithmetic or Geometric?

This is a Geometric sequence.

So *r* = 1.8

*a*_{4} = *a*_{3} · 1.8

*a*_{4} = 32.4 · 1.8

*a*_{4} = 58.32