We're looking for a solution of the form
. By the chain rule, this solution should have total differential

and the equation is exact if the mixed second-order partial derivatives of
are equal, i.e.
.
The given ODE is exact, since


Then




With
, we get


The amount of Tina money can be expressed in an exponent function like this:
an= $1100(1.0725)^n
The variable an represent the total money and variable n is the years needed to achieve that amount.
Then, the time needed for the money to reach $6,600 would be:
an= $1100(1.0725)^n
$6,600= $1100(1.0725)^n
$1,100(6)= $1100(1.0725)^n
6= (1.0725)^n
n= log1.075 6
n= 24.78
(150-45)/35 = the number of video games bought
It depends on the percentage rate of said tax... is the tax rate 5%? 20%?