<h2>Explanations:</h2>
From the given question, we have the following parameters
Cost of a small greeting card = $1.60
The cost of a large greeting card = $4.05.
Cost of 5 small greeting cards = 5(1.60)
Cost of 5 small greeting cards = $8.00
Cost of 4 large greeting cards = 4(4.05)
Cost of 4 large greeting cards = $16.2
Cost of 5 small and 4 large = $8.00 + $16.2
Cost of 5 small and 4 large $24.2
Hence it would cost $24.2 to get 5 small greeting cards and 4 large greeting cards
Similarly;
Cost of x small greeting cards = 1.60x
Cost of y large greeting cards = 4.05y
Cost of small greeting cards and y large greeting cards = 1.60x + 4.05y
Hence it would cost $(1.60x + 4.05y) to get x small greeting cards and y large greeting cards
