We have a table with inputs/outputs values of a sequence, so we need to find the formula of the sequence.
We can see that the following expression match the values in the table:
![\begin{gathered} \text{Input = n} \\ \text{Output}=n\cdot(n+1) \end{gathered}]()
If input = -5 the output is:
![\begin{gathered} \text{Input}=-5 \\ \text{Output}=(-5)\cdot(-5+1)=(-5)\cdot(-4)=20 \end{gathered}]()
The output = 20.
The rule in words is: The output is equal to input multiply the input plus one.
The rule in symbols if input is n:
![\text{Output}=n\cdot(n+1)]()