Respuesta :

Step-by-step explanation:

f(x) = x³ - 12x² + 45x -18

to find the interval of the function :

f'(x) > 0

3x²-24x+45 > 0

x²-8x +15 >0

(x-5) (x-3) >0

x<3 or x >5

the solutions :

{x < 3 or x > 5}