The slope formula is
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]we can use this formula by introducing the values of the given points. In our case
[tex]\begin{gathered} (x_1,y_1)=(8,8) \\ (x_2,y_2)=(1,9) \end{gathered}[/tex]Hence, we have
[tex]m=\frac{9-8}{1-8}[/tex]It yields,
[tex]m=\frac{1}{-7}[/tex]hence, the answer is
[tex]m=-\frac{1}{7}[/tex]