Answer:
Increasing:

Decreasing:

Explanation:
Critical points:
The critical points of a function f(x) are the values of x for which:

For any value of x, if f'(x) > 0, the function is increasing. Otherwise, if f'(x) < 0, the function is decreasing.
The critical points help us find these intervals.
In this question:

So

Critical point:





We have two intervals:
(0, 750) and

(0, 750)
Will find P'(x) when x = 1

Positive, so increasing.
Interval

Will find P'(x) when x = 800

Negative, then decreasing.
Answer:
Increasing:

Decreasing:
