Final answer:
After each year, the number of units in use will decrease by 2%. To find the number of units in use after n years, use the equation 8000 * 0.98^n.
Step-by-step explanation:
After each year, the number of units that will be in use will decrease by 2%. This can be represented by the equation: 8000 * 0.98^n, where n is the number of years.
So, to find the number of units in use after n years, we substitute n into the equation. For example, if we want to find the number of units in use after 3 years, we replace n with 3:
8000 * 0.98^3 = 8000 * 0.941192 = 7529.54
Therefore, after 3 years, approximately 7529.54 units will be in use.