The image shows a question from a set theory assignment. Here's what the questions mean:

1. An object in a set is called a(n) __________:

   • The correct term for this is "element." In set theory, any object contained within a set is referred to as an element of that set.

2. The symbols $x \in A$ mean __________:

   • This notation means "x is an element of A." It expresses that the object $x$ belongs to the set $A$.

3. The symbols $x \notin A$ mean __________:

   • This notation means "x is not an element of A." It expresses that the object $x$ does not belong to the set $A$.

Would you like further details on set theory or these concepts?

Here are five related questions you might want to explore:

1. What is the difference between a set and a subset?
2. What does the symbol $\subseteq$ represent in set theory?
3. How do you define the union and intersection of two sets?
4. Can an element belong to two sets simultaneously?
5. What is the complement of a set?

Tip: In set theory, the symbol $\in$ means "is an element of," while $\notin$ means "is not an element of." These are fundamental in defining relationships between objects and sets.