Dan has 340 dollars to spend on 9 book. After buying them he had 16 dollars. How much did each book cost? Answer with an equation.

340-9x=16

x is the cost of each book

Okay so you want to do the opposite operation of what it's asking you to do to isolate the variable. So subtract 16 from both sides and add 9x to both sides to get 324=9x

So just divide by 9 and get x = 36