Suppose two mice live in a barn. The number of mice quadruples every three months. The function f (x) = 2•4^x models this situation. How many mice will be in the barn after two years?

So first we have to see how many 3 months are in 2 years. There are 8 in 2 years, we do 2x4=8, and then 8x4=32, then 32x4=128, then 128x4=512, then 512x4=2048, then 2048x4=8192, then 8192x4=32768, then 32768x4=131072. So our answer is 131,072.