Answer :

[tex]b-9+6b=30 \\\\ 7b=30+9 \\\\ 7b=39 \\\\ \boxed{b=\frac{39}{7}}[/tex]
b - 9 + 6b = 30                :First, combine like terms

7b - 9 = 30                      :Then, add the 9 over to the other side

7b = 39                           :Then, divide the whole equation by 7

b = 5.57

Your final answer:

b = 5.57
or
b = 39/7