Pls help ill give brainlist

Strawberries cause two hours per pound kate buys 5 pounds he gets 20% off discount on the total cost how much does kate pay for the strawberries

Ifurniture stores having a weekend sale and is offering 20% discount on patio chairs and table the sales tax on furniture is 6.25 using function composition how can you represent the total amount a that you would need to pay for this furniture that cost x dollars

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?