Answer:
paperbacks are $8.99; hardcover books are $19.99.
Explanation:
Letting p and h represent the costs of paperback and hardcover books, respsectively, we can write two equations for the cost of a book purchase based on the problem statement.
... 5p +4h = 124.91
... 3p +2h = 66.95
If we subtract the first equation from twice the second, we can find the cost of a paperback.
... 2(3p +2h) -(5p +4h) = 2(66.95) -124.91
... p = 8.99 . . . . . simplify
Using this value in the second equation gives ...
... 3ยท8.99 +2h = 66.95
... 2h = 39.98 . . . . . subtract 26.97
... h = 19.99 . . . . . . . divide by 2
Paperbacks are $8.99; hardcovers, $19.99.