Answer:
It can be interpreted that Jessica will lose $10 per week if she does not know on any doors.
Step-by-step explanation:
Jessica earns a commission on each sale but has to pay for her own expenses.
The weekly earnings are shown as: 
Now, lets check how much she earns with each door knock or 'x'
When x = 5

When x = 6

When x = 7

We can see that with each increased 'x' (door knocks) , Jessica is earning $10.
Thus, it can be interpreted that Jessica will lose $10 per week if she does not know on any doors.