Question

A function is a rule that assigns each _____ exactly one ____.

Answer 1

input, output

Explanation:

A function is a rule that assigns each input exactly one output.

Some questions that have you check a list of points, a table of values, a graph or an equation, to figure out if its a function... you check to see if every x only has one y to go with it. This is what the vertical line test does also.