The operation $A \cup B$ represents the union of sets $A$ and $B$. The union of two sets includes all distinct elements from both sets.

Given:

• $A = \{-2, 5\}$
• $B = \{4, 7\}$

The union $A \cup B$ is: $A \cup B = \{-2, 5, 4, 7\}$

Final Answer:

$A \cup B = \{-2, 5, 4, 7\}$

Would you like a more detailed explanation or examples? Here are some related questions to explore:

1. What is the intersection of $A$ and $B$ ($A \cap B$)?
2. How do you find the difference between $A$ and $B$ ($A - B$)?
3. What is the cardinality (size) of $A \cup B$?
4. How is $A \cup B$ different from $A \cap B$?
5. Can a union operation involve more than two sets?

Tip: In a union operation, repeated elements between sets are written only once in the result.