In 1990, a restaurant had a profit

Of $40,000. In 1998 the company has a profit of $64,000. Find the rate of change of the restaurants profit in dollars per year

So you want to be able to see the increase and the amount of time that the increase happened in so you subtract 40,000 from 64,000 and 1990 from 1998

64,000-40,000 = 24,000

1998-1990=8

Now you have the profit increase and the number of years. Time is always your y value, and to find the rate of change you put your x over your y.

24,000/8

Now you have your rate of change as a fraction but that fraction can be simplified. To do this you divide x by y

24,000/8 = 3,000

Your rate of change is $3,000 per year.