The equation of a straight line on a graph is made up of a term, an term and a number, and can be written in the form of .
All the points that lie on the green line have a -coordinate that is the same as the -coordinate, eg:
We say that the equation of the line is .
All the points that lie on the purple line have a -coordinate that is one number higher than the -coordinate of the same line, eg:
In other words, the -coordinate equals the -coordinate .
So the equation of the line is .
What is the equation of the line shown below?
The coordinates of the points are , and .
Here, the value is always twice the value.
The equation of the line that fits these and values is: