What is 1/2 times 2 times 1.7

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

In which direction does the left side of the graph of this function point? a(x) = 3x - x2 + 4x - 2

20 ! brainliest ! add and simplify your answer.