Given f'(x)= (x-4)(4-2x) , find the x-coordinate for the relative maximum on the graph of f(x)

Question

A) 4
B) 3
C) 2
D) none of these

Answer 1

relative max is where
f' = 0 and f" < 0
So, it will be either at x=4 or x = 2
f" = 12-4x
so, f" < 0 at x=4