Zeus Industries bought a computer for $2280. It is expected to depreciate at a rate of 30% per year. What will the value of the computer be in 3 years?

This is an exponential growth/decay problem. It has a formula, and it doesn't matter which you have ... the formula is the same for both, except for the fact that you're rate is decreasing instead of increasing so you will use a negative rate. The formula is this: A = Pe^rt, where A is the ending amount, P is the beginning amount, e is euler's number, r is the rate at which something is growing or dying, and t is the time in years. Our particular formula will look like this: A = 2280e^ (-.30*3), Notice we have a negative number in for the rate (and of course it's expressed as a decimal!). First simplify the exponents: -.30*3 = -.9. On your calculator you have a 2nd button and a LN button. When you hit 2nd-->LN you have "e^ (" on your display. Enter in -.9 and hit enter. That should give you a display of. 4065695. Now multiply that by 2280 to get 926.98, the value of the computer after it depreciates for 3 years at a rate of 30% per year.