Data can be modeled by a linear equation if all of the points lay on the same line. This happens if every pair of points have the same slope, which we can calculate as
For example, the first two points have a slope of
The first and third point have a slope of
You can check that all the other pairs always share a slope of 4. This is enough to claim that the points lay on the same line.
To write the equation of the said line, we can use the following formula: given a point
and a slope
, the line passing through that point with that slope has equation
Plugging the coordinates of the first point (for example) and the slope we found out, we have