Answer
false
$\{\emptyset\} \subseteq \{\emptyset, \{\emptyset\}\}$
Work Step by Step
$\{\emptyset\} \not\subseteq \{\emptyset, \{\emptyset\}\}$
This is incorrect, for it should say:
$\{\emptyset\} \subseteq \{\emptyset, \{\emptyset\}\}$
Let's say:
$A=\{\emptyset\}$
$B=\{\emptyset, \{\emptyset\}\}$
We can see that A's only element is an empty set ($\emptyset$).
An empty set ($\emptyset$) is also an element of B.
Therefore: $A\subseteq B$
