Jack makes money every week from mowing lawns Every week he mows one more lawn than he did the previous week. Is this linear or exponential?

Step-by-step explanation:

That's linear.  You've got an arithmetic progression here, with first term a(1) and common difference d.

Amount of money charged by Luigi as fees = $140
Hourly rate of Luigi for each contract = $25
In the question there are more important information's already provided. Let us write them down first.
Total amount charged by Luigi for a project = y
Number of hours worked on the project by Luigi = x
Then the equation can be written as
y = 140 + 25x
Now
The amount earned by Luigi after 10 hours = 140 + (25 * 10) dollars
                                                                     = 140 + 250 dollars
                                                                     = 390 dollars
So the amount earned by Luigi after 10 hours is $390. I hope the procedure is clear enough for you to understand.