Would it be correct to assume that the instructions were to "solve"...? If so, what method are you supposed to use? (I would have moved the 63 to the other side, divided through by 7, and square-rooted, but you might be required to use some other method.)
If not, what did the instructions say? What have you tried? Where are you stuck? With which part or concept are you seeking "understanding"?
When you reply, please include a clear listing of your steps so far. Thank you.
Eliz.