Answer:
All real numbers greater than -3
Step-by-step explanation:
The domain of a log is the baseline is greater than 0.
Set x + 3 greater than zero and solve
x + 3 > 0
x > -3
It is not direct variation because it does not follow the equation
y = slopex
THE points do not make the equation true .
Answer:
Volume of the Figure 
Step-by-step explanation:
Volume of the figure = Volume of the Upper cone+Volume of the lower cone
Volume of a cone = 
Volume of the Upper Cone with



Volume of the Lower cone with
and 

Volume of the Whole Figure = 
Volume of the Figure 
Let

. Then

and

are two fundamental, linearly independent solution that satisfy


Note that

, so that

. Adding

doesn't change this, since

.
So if we suppose

then substituting

would give

To make sure everything cancels out, multiply the second degree term by

, so that

Then if

, we get

as desired. So one possible ODE would be

(See "Euler-Cauchy equation" for more info)