Slope can be defined as the change in y over the change in $x$.

Pick two whole-number points on the line.

The coordinates for these two points are $(10, 6)$ and $(5, 3)$. Now count the change in $y$ and the change in $x$.

$\frac{3}{5}$

Pick two points on the line.

These coordinates are $(5, 6)$ and $(0, 0)$.
Find the slope. See part (a) for help.

See part (a).