Rosa just finished installing a small koi pond in her back yard and now needs to re-sod. one side of the koi pond is 2 feet shorter than the other. one side of the garden is three times the longer side of the koi pond; and the other side of the garden is five feet longer than the first side. how much sod does rosa need to buy?

The sketch of the garden and the pond is shown below

Area of garden = length × width
Area of garden = [3x + 5] × 3x
Area of garden = 3x[3x+5]
Area of garden = 9x² + 15x

Area of pond = [x-2] × x
Area of pond = x[x-2]
Area of pond = x² - 2x

Area to be re-sod = Area of garden - Area of pond
Area to be re-sod = 9x² + 15x - [x² - 2x]
Area to be re-sod = 9x² - x² + 15x + 2x
Area to be re-sod = 8x² + 17x

The amount of sod needed to be bought would depend on how much in each packaging they are being sold.

The 8th term is 512