Directions: Use the function f(x) below to answer the following questions. f(x) = -7x+9 Find the open interval(s) on which f is increasing / decreasing. 1. Increasing: 2. Decreasing: Answer Formats If necessary, use -INF and INF to denote - and co. If the function is not increasing / decreasing for any interval, enter NONE. If there is more than one interval, type your answer as a comma separated list. For example: (a1, a2), (b1, b2).