, , , ,

This is an arithmetic sequence since there is a common difference between each term. In this case, adding to the previous term in the sequence gives the next term. In other words, .

Arithmetic Sequence:

This is the formula of an arithmetic sequence.

Substitute in the values of and .

Apply the distributive property.

Multiply by .

Add and .

Identify the Sequence 9 , 2.5 , -4 , -10.5 , -17