Please help me with this. I get stuck at the part:

(5(x + h) - 4) - (5(x) - 4)/x + h - x

What do I do after that? Do I continue with this?

(5(x + h) - 4) - 5(x) + 4/h

after..

5x + 5h - 4 - 5(x) + 4/h

5h/h

Please help me I am utterly confused on how to solve this problem. Thank you so much in advanced