Question

Which is an equation of a direct proportion?

a. y=-2x
b. y=1/2x-2
c.y=-2x+3
d. y=4/x

Answer 1

a. y=-2x

Explanation:

The equation of a direct proportion is of the form
`y=kx` where k is the constant of proportionality.

From the given options, the only equation that is of the form,
`y=kx` is

`y=-2x`.

In this case
`k=-2` is the constant of proportionality.

Therefore the correct option is A.