Answer:
critical number: 26.6667
increasing from (-∞, 26.6667) and decreasing from (26.6667,∞)
Explanation:
1) find the derivative:
derivative of f(x) = 16-0.6x
2) Set derivative equal to zero
16-0.6x = 0
0.6x = 16
x = 26.6667
3) Create a table of intervals
(-∞, 26.6667) | (26.6667, ∞)
1 27
Plug in these numbers into the derivative
+ -
So It is increasing from (-∞, 26.6667) and decreasing from (26.6667,∞)