Answer:
60 accounts for the money earned per month.
-450 accounts for costs incurred as explained below.
Step-by-step explanation:
The coefficient 60 accounts for the money earned per lawn per day. Thus if they maintain 5 lawns for 2 days each, we get a total earning of 60 * 5 * 2.
This would equal $600.
The coefficient -450 accounts for the cost incurred when working for a day.
This would most probably be the pay (per day rate) of the company employee maintaining the lawn. This coefficient thus accounts for the pay of the workers in the company.
This is so because profit = total money earned - total money spent
And with -450 we would be accounting for the money spent on pay or other things such as loan of equipment and fertilizer use etc.