The equation that represents a proportional relationship is:
y = 32x
Because:
y/x = 32
So that implies that y is directly proportional to x.
Note that other equations represent a proportional relationship in some form, only that the relationship y = 32x is the only direct proportional relationship.
The answer is x= 1/5 or 0.2
The discontinuity are the point wherein the function is not defined.
The zeros are the points wherein f(x)=0.
Computing the discontinuity points:
Set

then the discontinuity point is at

.
Comptine the zeroes:
Set

Compute the discriminant:

Then with quadratic formula we get the solutions:

The two zeros are
15 8's. 8,18,28,38,48,58,68,78,88,98,108,118,128,138