If you want to find “x” you would need to isolated isolate the variable “x”. You do This by doing the inverse operation of the equation.
For example,
If you add 39 you’ll subtract 39.
But in this case ask yourself,
What variable do I want?
In this case it’s “x”
What is stopping “x” form being by itself?
Then do the inverse operation to get rid of what stopping x form being by itself.
If you don’t want x I’m sorry I wasn’t of help.