Respuesta :

christinann062
13 = r/9 + 8

subtract 8 from each side

5 = r/9

multiply 9 from each side

r = 45
13 = r/9 + 8

Subtract 8 from the both sides, 
5 = r/9

Now, multiply both sides by 9, 
45 = r

In short, Your Answer would be 45

Hope this helps!