Answer
$125$
$700$
Work Step by Step
This is an arithmetic sequence, we have $a_1=-3, d=4$, $a_n=a_1+4(n-1)$ and $S_n=\frac{n}{2}(2a_1+4(n-1))$, thus we have:
the 33rd term: $a_{33}=-3+4(33-1)=125$
the sum of the first 20 terms: $S_{20}=\frac{20}{2}(2(-3)+4(20-1))=700$
