Whigh relation is a function

A relation is considered a function if every input (or "x" value) is associated with exactly one output (or "y" value). This means that if you were to map the inputs and outputs on a graph, each x-coordinate would hit the y-axis only once. Imagine throwing balls into a series of buckets: if each ball can land in only one bucket (and never spills over into two), you've got a function! In practical terms, functions are super useful and show up everywhere, from calculating your monthly expenses based on your income to programming algorithms that recommend your next favorite movie. Even in nature, functions help us model everything from the growth of plants to the trajectory of a thrown ball, making them central to science, engineering, and everyday life.