Hey there!
You can solve this by getting b to one side of the equal sign and everything else on the other side by completing the following steps:
[tex]63=5b+13[/tex] (subtract 13 from both sides)
[tex]50=5b[/tex] (divide both sides by 5)
[tex]10 = b[/tex] (final answer)
Your solution will be 10.
Hope this helped you out! :-)