Answer
$-a^3+8a^2-2a+3.$
Work Step by Step
We divide each term of the polynomial by the monomial as follows
$$
\frac{4a^5 - 32a^4 + 8a^3 - 12a^2}{-4a^2 }= \frac{4a^5 }{-4a^2 }+\frac{ - 32a^4 }{-4a^2 }+\frac{ 8a^3 }{-4a^2 }+\frac{ - 12a^2}{-4a^2 }\\
=-a^3+8a^2-2a+3.
$$
