2 Find the local max and min of the function f(d) = 12 - 12d 9d^2 - 2d^3. (4 marks Application, 2 marks Communication) 3 Find the concavity of the function f(x) = x^3 - 6x^2 9x 2 (state the intervals which are concave up and concave down). (4 marks Application, 2 marks Communication) 4 A town models its property tax revenue, in thousands of dollars, with the equation y = 3(x - 5)^2 - 16x(SQRT(x)), where x represents the number of new houses built. How many new houses represent the minimum number required to sustain this town