Answer:

Explanation:
Ok, I gotchu. Dividing fractions is just like multiplying except you flip the second fraction:
So you can rewrite it as:
*

Then, when you multiply straight across you will get
-4a (because of distributive property) on the numerator. On the denominator, it is 3a.
To simplify, you must factor an a out of the numerator which looks like this: a(a-4)
So now we have
and are able to cancel out an "a" as it is being multiplied on both the top and bottom.
This gives you your answer of:

I hope this helps :)