(a-28)/8 = 1.64
What does a equal?

Here you need to get rid of 1/8 and then get ride of the -28

you do this by doing things to both sides of the equation

To start, you need to multiply both sides by 8, then you need to add 28 to both sides, this will give you the value for a.

let me know if you need me to explain anythign in more depth :)