Here's a way to do it.
Let 4e +2 = 5n +1 . . . . . . for some integer n
Then e = (5n -1)/4 = n + (n -1)/4
We want (n-1)/4 to be an integer, so let it be integer m.
... m = (n -1)/4
... 4m = n -1
... 4m +1 = n
Substituting this into our expression for e gives
... e = (5(4m+1) -1)/4 = (20m +4)/4 = 5m +1
e = 5m+1 for any integer m
-12c to the fourth power +18c to the third power! :)
In Cartesian coordinates, the region is given by

,

, and

. Converting to cylindrical coordinates, using

we get a Jacobian determinant of

, and the region is given in cylindrical coordinates by

,

, and

.
The volume is then
2/cos x
........................
For this case we must indicate which of the equations shown can be solved using the quadratic formula.
By definition, the quadratic formula is applied to equations of the second degree, of the form:

Option A:

Rewriting we have:

This equation can be solved using the quadratic formula
Option B:

Rewriting we have:

It can not be solved with the quadratic formula.
Option C:

Rewriting we have:

This equation can be solved using the quadratic formula
Option D:

Rewriting we have:

It can not be solved with the quadratic formula.
Answer:
A and C