Answer:8 dollars per book
Explanation:
Keith started with 81 dollars, and hadd seventeen dollars left over. Subtract 81 from 17 and you will get how much he spent. 64 dollars spent to buy books. Next you would divide 64 by 8, because 8 is the amount of books he bought. 64 divided by 8 is 8. So each book cost 8 dollars
Equation: (81-17) divided by 8