Algebra-2

Question Analysis
This question tests the understanding of the definition of a function using a mapping diagram. The key is to check if each input value points to only one output value.

Key Concept Explanation
A function is a special type of relation where each element in the domain corresponds to exactly one element in the range.

Step-by-step Solution
1. List all input values: 1, 2, 1.
2. Check if each input value points to only one output value: The input value 1 points to both output ...