It's A because 8-15 is -7 but the absolute value parenthesis make it positive 7.
First example:
Subtract the 8n on both sides to get the variable on one side of the equation. Do the same for the regular numbers. Then divide by -3.

This should be your final answer.
Second Example:
Do the same thing as explained in Example 1. Here's some work to help guide you.

That should be your final answer here.
Third Example:

Hope this helps and its understandable! Let me know if you still don't understand.
Answer:
<h2>14</h2>
Step-by-step explanation:
Look at the picture.