Hey there!
The answer to your question is

To find
, we must isolate the variable. Given the equation:
First, we add like terms:

Now, we subtract
from both sides of the equation (Remember: What you do to one side of an equation, you must do to the other side!)

Finally, we divide both sides by
.

Hope this helps and have an amazing day! I would love to help you if you need any more assistance. If you do, let me know!