What will this site do for you?
This site will determine the line that goes through the two given points. There are 4 possible outcomes:
One case is even more strange: You won't get a function, but a relation to describe the line. The point is that a function has only one input value per output value. This constraint is violated if you provide points that have both y equal. Families of functions have additional parameters aside to the independent variable (x). This case occur if you provide only one point. It is clear that the result set of functions that matches the criteria to pass this point is infinite. So you have two possibilities to formulate the function. Either you vary the slope (a) or the intersection with the xaxis. After all it doesn't matter which way you choose. 
Two points line
Calculates function parameters for a line that goes through two points.




Links https://www.mathsisfun.com/algebra/lineequation2points.html https://www.youtube.com/watch?v=4il4haYASys https://www.khanacademy.org/math/algebra https://www.youtube.com/watch?v=rzUJatVndcY 