Answer:
Input is the number in the first column of the table. This is the number that you start with to follow the rule if the rule is given. You would also use this number to figure out what the rule is if it is not given.
Step-by-step explanation:
An input-output table, like the one shown below, can be used to represent a function. Each pair of numbers in the table is related by the same function rule. That rule is: multiply each input number (\begin{align*}x\end{align*}-value) by 3 to find each output number (\begin{align*}y\end{align*}-value).
