The slope of a graph can be found using the formula:
slope = (change in y)/(change in x)
Given the points (4, 6) and (6, 6), the change in y is 6 - 6 = 0, and the change in x is 6 - 4 = 2.
So, the slope of the graph is 0/2 = 0.
Therefore, the slope of the graph is 0.