The earning of the salesperson is an illustration of a linear function.
The possible functions in the two scenarios are:
and 
The function is given as:

When the base salary is increased, a possible function is:

This is so, because 2500 is greater than 2000
When the commission rate is decreased, a possible function is:

This is so, because 0.05 is less than 0.1
So, the possible functions in the two scenarios are:
and 
See attachment for the graphs of both functions
Read more about linear equations at:
brainly.com/question/21981879