What expression has a negative value? X+y, x-y, x•y or x over y

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

Abus travels 36 miles in 45 minutes. enter the number of miles the bus travels in 60 minutes at this rate.

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.