The term which represents the cost of the shoes after the discount is:
(1 - 0.25)s.
Let c represents the total cost of clothes.
and s represents the cost of shoes before the offer.
This means that Declan has to pay (1-0.25) of the actual cost for shoes.
This means that the cost of shoes will be: (1-0.25)s
Also, there was a 8% tax on the total purchase.
i.e.
The expression representing his total cost is:
c + (1 - 0.25)s + 0.08[c + (1 - 0.25)s].