For this task you need the following basic knowledge: Linear function
Consider the set of points for different .
To find the general equation of a straight line, we need two points on the straight line.
Therefore, it is best to choose here e.g. the two points and .
First determine the slope .
Now you can insert and one of the points, e.g. , into the general line equation.
Wrtite down the equation of the straight line.