[tex]-13=\frac{r}{9}+8[/tex]
First you had to switch sides of equation form.
[tex]\frac{r}{9}+8=-13[/tex]
Then you subtract by eight from both sides of equation form.
[tex]\frac{r}{9}+8-8=-13-8[/tex]
Simplify.
[tex]\frac{r}{9}=-21[/tex]
Next, multiply by nine from both sides of equation form.
[tex]\frac{9r}{9}=9(-21)[/tex]
Finally simplify by equation.
[tex]9*-21=-189[/tex]
[tex]r=-189[/tex]
Final answer: [tex]\boxed{r=-189}[/tex]
Hope this helps!
And thank you for posting your question at here on brainly, and have a great day.
-Charlie
