By the way, a solution may not seem to be explained very well if you are given guidance on how to solve the question but you do not understand the basic algebra underpinning that guidance.
Despite what you might think, it is not helpful to give you an entire solution. Post #2 gave you everything except the last step but you did not understand it. I have said the reasons why.
Do yourself a favor and review the basic material so that you can understand the help that people are trying to give you.