SOLUTION: If a store prices each book at $x, (64 − 8𝑥) books will be sold.
(i) The total amount of money earned from the sale of the book is $y. express y in
terms of x
The total amount of money y, earned from the sale of (64-8x) books, equals
to the product of the number of books (64-8x), by the price of each book x
y = (64-8x)*x,
or
y = 64x - 8x^2,
which is the same as
y = -8x^2 + 64x.