Since it's a straight line, the slope will be constant for all of the points.
To find the slope, we need to take the difference between the rise and the run:
[tex]m = \frac{y_1 - y_2}{x_1 - x_2}[/tex]
Let's take (2, 10) and (1, 7)
[tex]m = \frac{10 - 7}{2 - 1}[/tex]
[tex]m = \frac{3}{1}[/tex]
[tex]m = 3[/tex]
Hence, the slope of the function is 3