Suppose the given coordinates are represented as,
[tex]\begin{gathered} (x_1,y_1)=(4,2) \\ (x_2,y_2)=(7,6.5) \end{gathered}[/tex]Then, the formula for slope can be expressed as,
[tex]\begin{gathered} m=\frac{y_2-y_1}{x_2-x_1} \\ m=\frac{6.5-2}{7-4} \end{gathered}[/tex]Solving it,
[tex]m=\frac{4.5}{3}=1.5[/tex]The slope is 1.5.
The formula of (10, 8) anjd (-5,8) is
[tex]m=\frac{8-8}{-5-10}[/tex]