Answer
$\{\},\{-2\},\{4\},\{9\},\{-2,4\},\{-2,9\},\{4,9\},\{-2,4,9\}$
Work Step by Step
We say that $A$ is a subset of $B$ if $B$ contains all elements in $A$.
Hence here the subsets are: $\{\},\{-2\},\{4\},\{9\},\{-2,4\},\{-2,9\},\{4,9\},\{-2,4,9\}$