Algebra-1

Question Analysis
This question involves the criteria that distinguish functions from non-functional equations.
The main focus is on recognizing that only equations with unique outputs qualify as functions.

Key Concept Explanation
All functions can be written as equations, but not all equations are functions. The critical difference is the "unique output" requirement: if an equation allows one input to produce multiple outputs (e.g., ), it fails to be a function.

Step-by-step Solution
Understand the condition: "does not satisfy one input → one output" means it lacks the key property of functions.
Conclude that such an equation cannot be a function.

Common Mistakes
Assuming all equations are functions. For example,