Hello.
Parallel lines have the same slope.
If the given line has a slope of [tex]\displaystyle-\frac{8}{9}[/tex], then the line parallel to it has the same slope.
Thus, line r has a slope of [tex]\displaystyle-\frac{8}{9}[/tex].
I hope it helps.
Have a great day.
[tex]\boxed{imperturbability}[/tex]