Please assist in solving A B C. Not getting a consistent answer

Marques has a rectangular backyard that measures 80 feet by 60 feet. He wants to make a garden, and he decides he will place brick pavers to form a uniform border around the sides of the garden so he may walk around without trampling any plants. He is considering several sizes of pavers, so he lets : represents the width of the border, as shown below. Enter answers in the form: Ax^2+Bx+C,n,m without extra spaces. (a) Find a polynomial that represents the area of the garden in square feet. (b) Find the area of the garden if he uses pavers that are 5 feet in width. (c) If he wants his garden to be 3,744 square feet, what size pavers should he use? X Garden 60 X 80