How do you add #(12a^5 - 6a - 10a^3) - (10a - 2a^5 - 14a^4)#?
All you have to do is distribute the negative through the second half of the equation
Rewriting your equation you get
Now you can look to see if you can combine like terms, i.e. terms that have the same degree of "a" in them.
The final answer, after adding up the like terms, is