Does the equation y= -4x represent a proportional relationship?

Since the equation for y only has a constant multiplying x, it is said that it represents a proportional relationship.

In a proportional relationship, the output variable is given by the input variable multiplied by a constant of proportionality.

In this problem, the output variable is:

In which:

Thus, it is a proportional relationship.

A similar problem is given at link

Proportional quantities can be described by the equation y = kx, where k is a constant ratio. You can tell that the relationship is directly proportional by looking at the graph.

So yes it does equal a proportional relationship.

c. 4 and 1/2 pounds is the answer! : )