Answer:Let x be the cost of a hard-cover book and y be the cost of a paperback book.
We know that Steve spent 2 hard-cover books and 3 paperback books. So we can write the equation as:
2x + 3y = 50 - 15.5
2x + 3y = 34.5
We also know that he was planning to buy 3 hard-cover books and 4 paperbacks, so we can write another equation as:
3x + 4y = 50
Now we have a system of two equations with two unknowns:
2x + 3y = 34.5
3x + 4y = 50
We can use the first equation to eliminate one variable by multiplying both sides by 2 and then subtracting 3y:
4x + 6y = 69
3x + 4y = 50
x = 19.5
Now we can substitute this value of x into the second equation and find the value of y:
3(19.5) + 4y = 50
58.5 + 4y = 50
4y = -8.5
y = -2.125
Therefore, the cost of a hard-cover book is $19.5 and the cost of a paperback book is $-2.125.
Note that the cost of a paperback book is a negative value which is not possible in this case. It means that the given information does not have a solution.
Explanation: