Question

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

Answer 1

Treat a/k as a variable, and solve for a/k.

Answer 2

2(a/k)+1=9
2(a/k)=8
(a/k)=8/2
(a/k)=4

Answer 3

You may substitute y for a/k to make it look simpler.
Let y = a/k, then
2y + 1 = 9
Solve for y.

Answer 4

4 do it backwards,
9-1=8
8/2=4
a/k=4