Part Ill: Thinking [18 marks] 12. Write the equation of rational function with vertical asymptotes of x = 1 and x = -1, horizontal asymptote of y = , and x-intercepts of 3 and -3. Sketch it and show your full solution. (6 marks) 13. An economist for a sporting goods company estimates the revenue and cost functions for the production of a new snowboard. These functions are R(x) = -x + 10x and C(x) = 4x + 5, respectively, where x is the number of snowboards produced, in thousands. The average profit is defined by the function "( where P (x) is the profit function. Determine the production levels that make AP (x) 20. (6 marks)