Given:
The equation is

To find:
Whether the equation represents a direct variation. If it does, find the constant of variation.
Solution:
The general equation of direct variation is
...(i)
Where, k is the constant of variation.
The equation of direct variation is always true for (0,0).
The given equation is

It can be written as

...(ii)
For x=0,


The given equation is true for (0,0). So, it represents a direct variation.
On comparing (i) and (ii), we get

Therefore, the constant of variation is
.