Question 709914
If they all fit one linear function, then they would be "collinear", and there are two things you could do to check.

(1) Plot the points on cartesian paper and you should be able to draw a line that contains all of them;

(2) Calculate the slope from or between each pair of points.  All the slopes must have the same value.  



Once you know that they are on the same line, find the x and y intercepts; either from the graph, or by calculation with slope intercept form of equation for a line, y=mx+b; you would already have found the slope, so you'd pick a point (x,y) and find b.