Question

consider the table of input and output values shown. drag a number to each box to complete the table of values to represent a function.
input 1 7 □ 2 □ 4 □
output 4 16 11 12 15 20 9
available numbers: 1, 2, 3, 4, 5, 6, 7

Explanation:

Step1: Recall function definition

A function maps each input to exactly one output, so no input value can repeat.

Step2: List used inputs

Used inputs: $1, 7, 2, 4$

Step3: Select unused inputs

Available numbers: $3,5,6$ (these are not in the used input list, so they will not create duplicate input mappings).

Step4: Assign to empty input boxes

We can assign the remaining unique numbers to the empty input slots in any order, as long as each input is unique. One valid assignment is:
First empty input: $3$, Second empty input: $5$, Third empty input: $6$

Answer:

The completed input row (from left to right in empty boxes) can be $\boldsymbol{3}$, $\boldsymbol{5}$, $\boldsymbol{6}$ (other valid assignments using the unused unique numbers $3,5,6$ in any order are also acceptable, as long as no input value repeats).