Originally Posted by

**OverclockerR520** Hello,

In class I am breifing chapter 4 through 4.5 then we are jumping to 9 so I have to get 4 down quickly. In my homework are two questions I'm getting fustrated on. The first should be simple since its basically substituiting for variables. The second delts with the relationship between ln and to the power variable "e". Any help would be much appreciated as I have typed out the questions in full below, thanks!

__Question on Chapter 4__

Some lending institutions calculate the monthly payment M on a loan of L dollars at an interest rate r (expressed as a decimal) by using the formula

where and t is the number of years the loan is in effect

a) Find the monthly payment on a 30–year $90,000 mortgage if the interest rate is 7%

b) Find the total interest paid on the loan in (a).

c) Find the largest 25–year home mortgage that can be obtained at an interest rate of 8% if the monthly payment is to be $800.

__Question on LOG and LN__

The Jenss model is generally regarded as the most accurate formula for predicting the height of preschool children. If y is the height in cm and x is the age in years, then

for years.

What is the height of a typical two year old?