Emma bought 3 copies of a book on Amazon. The total cost of the 3 books were $9.00, which includes $1.50 in shipping. Which equation best represents the cost of one book?
x/x is a fraction.
3x = 9
x/3 -1.50 = 9
3x + 1.50 = 9
9 + 1.50 = 3x