Answer:
i think the first graph is the correct
Answer: 
Step-by-step explanation:
The formula for finding the nth term of an arithmetic sequence is given as:

first term = -15
common difference = -6 - (-15) = 9
number of terms
substituting into the formula , we have :


Answer:

Step-by-step explanation:
we have

Adds the terms
Group terms that contain the same variable

Combine like terms

where

therefore
