How do I find the relative maximum and minimum and the zeros of f(x)=-x^3+16x^2-76x+96??

1 answer

since cubics are hard to solve, look for an easy root first:

-x^3+16x^2-76x+96
a quick synthetic division yields
-(x-2)(x^2-14x+48)

Now you have a quadratic which you can easily solve.

as for maxmima and minima, have you checked the first derivative yet? What did you find?