Answer:
The equation is 5x + 2y = 20
Step-by-step explanation:
Total money Derek has = $20
Cost of hardcover books = $5
Cost of paperbacks = $2
We need to find equation in standard form that determines the number (x) of hardcover books and the number (y) of paperback books he can buy.
Total cost of x hard cover books = 5x
Total cost of y paperback books = 2y
He has $20
So we have
5x + 2y = 20
The equation is 5x + 2y = 20