Assume the sustainability lead of a company is focused on reducing the net carbon footprint of the company by acquiring carbon credits via planting trees in collaboration with a local NGO focused on tree plantation. The sustainability lead needs to identify the optimal area of land to use for the project based on the overall economic efficiency of the project (that is, the lead intends to maximize the net benefits of the project). Based on data for similar projects done by the NGO in the past, the total benefits (TB) and total costs (TC) can be estimated using the equations below, where x is the size of the land in acre-ft.

TB = 12x + 300x2 TC = 58x + 100x2 + 1.5x3

What is the optimal size of the land to be used for tree plantation? (10 points)