For each set of the following total revenue and total cost functions, first express profit as

For each set of the following total revenue and total cost functions, first express profit π as a function of output x and then determine the maximum level of profit by finding the vertex of the parabola:

(a) TR = −6x2 + 1200x, TC = 180x + 3350

(b) TR = −4x2 + 900x, TC = 140x + 6100

(c) TR = −7x2 + 4100x, TC = 600x + 12,500

(d) TR = −9x2 + 6600x, TC = 660x + 19,600