a. To use the fact that (-1)(-1) = 1 to find -4 • (-9), what do you do first? A. Write each factor as the product of -1 and a positive number. B. Write each factor as the product of 1 and a negative number. C. Write each factor as the product of 1 and a positive number. D. Write each factor as the product of -1 and a negative number. b. Find the product - 4 • (-9).