After having done this on paper:

We want to isolate the variable, and the first step is to subtract the 8.

Since the <em>n</em> is being multiplied by 3, and that = 8, we can multiply both sides by 3.
<em>n</em> = 24
Let me know if this helped you understand better.
Also, you can check this by substituting in 24 for <em>n</em>.