Use Newton's method to estimate the two zeros of the function f(x) = x - x - 12. Start with X = - 1 for the left-hand zero and with x = 1 for the zero on the right. Then, in each case, find x,. Determine X2 when X = - 1. X. (Simplify your answer. Round the final answer to four decimal places as needed. Round all intermediate values to four decimal places as needed.)