okay so first let's identify all the like terms in this equation
- 8 & - 22
-5a^2, - 19a^2, 12a^2
-5a, -14a, -2a
we can combine each of these sets of like terms separately and then write them all out together
so combining - 8 and - 22 is - 30
- 5a^2 and -19a^2 is -24a^4, then combining it with positive 12a^2 leaves you with -12a^2
-5a, -14a, - 2a is - 21a
so we have - 30 - 21a - 12a^2 as a finished result
however if your teacher wants you to factor then you have:
3(-7a - 4a^2 - 10)
or
-3(7a + 4a^2 +10)