Easy calc problem help (10 pts for best answer)!!?

f is increasing when f' is positive. It's decreasing when f' is negative.

First, find where f' is 0 or dne:

0 = 3 − 5x²

x = ±√⅗

So the intervals to look at are:

(-∞, -√⅗)

(-√⅗, √⅗)

(√⅗, ∞)

Pick a value of x that is within each interval to determine the sign of f' in that interval. For example, we can test the first one by looking at x = -1:

f' = 3 − 5(-1)²

f' = -2

f' < 0

For the next one, look at x = 0:

f' = 3 − 5(0)²

f' = 3

f' > 0

Finally, look at x = 1:

f' = 3 − 5(1)²

f' = -2

f' < 0

So f is increasing on the interval (-√⅗, √⅗) and decreasing on the intervals (-∞, -√⅗) and (√⅗, ∞).

that's easy m8