Question

if 2(a/k)+1=9 , what does a/k equal?

Answer 1

$$
2(a/k)+1=9\\
\implies \cfrac{a}{k}+\cfrac{1}{2}=\cfrac{9}{2}\\
\implies \cfrac{a}{k}=-\cfrac{1}{2}+\cfrac{9}{2} =\cfrac{8}{2}=4
$$
Make sense?

Answer 2

yes thank you :)