Bella plans to put $200 into a savings account. she can place her money into an account represented by p(x) = 3x + 200, or into another account represented by n(x) = 200(1.04)x. which account has the highest value in 4 years? which account has the highest in 15 years?

The first is linear and the second is exponential.  In this case the exponential function will always be worth more, and it will become even exponentially :P greater than the linear function the more time that goes by...

p(4)=$212.00, p(15)=$245.00  for the linear function:

n(4)=$233.97, n(15)=$360.19  (to nearest cent respectively)

Note: n(x) should have been expressed as n(x)=200(1.04)^x  so that it is clear that 1.04 is raised to the power of x.