Question

Which equation shows a proportional relationship between x and y?

Answer 1

Given:

There exist a proportional relationship between x and y.

To find:

The equation which represents a proportional relationship between x and y.

Solution:

If there exist a proportional relationship between x and y, then

$y\propto x$

$y=kx$

where, k is constant of proportionality.

We know that, proportional relationship passes through the origin because (0,0) satisfy $y=kx$.

For x=0, check which equation has y=0.

In option A, $y=-3(0)-2=-2$.

In option B, $y=9$.

In option C, $y=4(0)=0$.

In option D, $y=3(0)+1=1$

Only in option C, we have a equation of the form $y=kx$ with 4 as constant of proportionality and it passes through (0,0).

Therefore, the correct option is C.