Question 185675
To solve, you need to see what you can reduce. Look at each term or variable or coefficient separately. Also, below / will mean divide.
First, -10/5=-2
Then look at your a variables. 
a^5 over a would reduce to a^4
Lastly, look at your b variables.
b over b^4 would reduce to b^3 but it has to remain in the denominator. 
So, on top you would be left with -2a^4 and on the bottom you would be left with b^3, and the entire answer would be:
-2a^4/b^3

Hope this helps. Good luck! Sandy :-)