Find the open intervals where f (m) is concave up and where it is concave down. Enter the your answer in interval notation. For example, if the function is concave up when −10 < m < 2 as well as when 4 < m < 7, then you would enter (-10, 2) U (4,7). f (m) = m² - 8m³ +5 concave down intervals: concave up intervals: