You can find the slope using the following formula:
[tex]\text{Slope}=m=\frac{y_2-y_1_{}}{x_2-x_1}[/tex]Where:
[tex]\begin{gathered} (2,-1)=(x_1,y_1) \\ (10,-3)=(x_2,y_2) \end{gathered}[/tex]Therefore:
[tex]m=\frac{-3-(-1)}{10-2}=\frac{-2}{8}=-\frac{1}{4}=-0.25[/tex]