Just double checking to make sure I got the correct answer because it is not the answer the book gives.
I need to find the maximum and minimum value
so I got the derivative and solved for f'(x) = 0
the derivative being
solving f(x) for x = -2,1,4, I got the answers
and so the max is 2 and min is -8/5 but the book has the max at 2 and min at -2
Is my work correct?