Answer
The sequence is arithmetic.
Work Step by Step
The given sequence is
$-3,6,15,24,...$
Calculate ratio between each pair of consecutive terms.
$\frac{6}{-3}=-2$
$\frac{15}{6}=\frac{5}{2}$
$\frac{24}{15}=\frac{8}{5}$
There is no common ratio.
So, the sequence is not geometric.
Calculate difference between each pair of consecutive terms.
$6-(-3)=6+3=9$
$15-6=9$
$24-15=9$
The common difference is $9$.
So, the sequence is arithmetic.
