(a) need to find the number of books, we'll call it "b". then the money (6w) minus the cost of books (17b) equals change left over (w)
6w - 17b = w
6w - w = 17b
5w = 17b
(5/17)w = b
(b) if w = 34
(5/17) *34 = b
10 = b
Fourth one since x is 2 and the y is 1
First we want to find how much it costs for 1 stamp, so we do 8.28 divided by 18, which equals 0.46. Then, we multiply 0.46 and 12, which is 5.52. Therefore, it would cost $5.52 to buy 12 stamps.
