The slope is given by:
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]In thie case we have:
[tex]\begin{gathered} m=\frac{4-(-2)}{18-(-12)} \\ =\frac{4+2}{18+12} \\ =\frac{6}{30} \\ =\frac{1}{5} \end{gathered}[/tex]therefore the slope between this points is 1/5.