In this form, k is the constant of variation and k≠0. Before we can write a direct variation equation, we should first find out if a direct variation exists for this relation. We will start by solving the general direct variation equation for m.
y= mx ⇒ m=y/x
To determine if y varies directly with x for the given relationship, we must find the value of k for each ( x, y)-coordinate pair. If k is the same for all four pairs, we will know for certain that a direct variation exists.
Game, x
Points, y
y/x
k
2
4
4/2
2
3
5
5/3
5/3
4
6
6/4
1.5
5
7
7/5
7/5
Notice that the value of k is different for all pairs. This means that y does not vary directly with x.
