Explanation:
To find extreme values, take the first derivative

Solve the equation for x.

or


or

We then get

or

So our extreme values occur at x=4/3 and x=4
Zeroes:






So we have a double root at 4, and a root of 0. We have two positive roots and one non negative root
End behavior:
Since we have a negative leading coefficient and a odd degree, as x becomes more positive, y will become negative and as x becomes more negative, y will become positive.