These are colinear points, because (9-5)/(4-2)=(11-9)/(5-4)=(15-11)/(7-5)=(21-15)/(10-3)=2 (slope of the line).
The graph of the line containing all these points is y=2x+b, where b can be found by substituting just one point's coordinates: 5=4+b, so b=1 and y=2x+1. By substituting the x value for each point in this equation, the accompanying y value can be checked. For example, put x=10 then y=21 and point (10,21) is in the set. Although the given pairs of values have been treated as if they were points on a graph, they could also be simply treated as numbers related by an equation, in this case, y=2x+1, where x is the first number in each pair.
