Read the Math Notes box in this lesson and then answer the following questions. The cost of a large flat-screen television is decreasing 20% per year.

1. What is the multiplier?

   Step 1(a):

   Subtract the percent from $1$.

   Answer (a):

   $0.8$

2. If a $50$-inch flat-screen now costs $$1200$, what will it cost in three years?

   Hint (b):

   The equation for an exponential function is: $y=a·b^x$

   More help (b):

   $a=$ initial value
   $b=$ multiplier
   $x=$ # of years

   Answer (b):

   $\$614.40$

3. Using the same rate, what did it cost two years ago?

   Hint (c):

   Use the same equation as (b) and do not change the multiplier.

4. Write the equation of a function to model this situation.