Take the homogeneous part and find the roots to the characteristic equation:

This means the characteristic solution is

.
Since the characteristic solution already contains both functions on the RHS of the ODE, you could try finding a solution via the method of undetermined coefficients of the form

. Finding the second derivative involves quite a few applications of the product rule, so I'll resort to a different method via variation of parameters.
With

and

, you're looking for a particular solution of the form

. The functions

satisfy


where

is the Wronskian determinant of the two characteristic solutions.

So you have




So you end up with a solution

but since

is already accounted for in the characteristic solution, the particular solution is then

so that the general solution is
The answer is 60m
You must multipy base x height x width to find the volume of a rectangular prism
6 3/4 hours = (6*60)+45 = 405 minutes
7/5 = 1,4
405 minutes * 1,4 = 567 minutes
= Jack spent 9 3/4 hours