Пошаговое объяснение:
f'(x) = x^3 - 6x^2 + 8x = x(x^2 - 6x + 8) = 0
x(x^2 - 6x + 8) = x(x - 2)*(x - 4)
x = 0
x = 2
x = 4
- + - +
024
\ / \ /
На промежутке [-1;3]
xmax = 2
xmin = 0
fmax(2) = 1/4*2^4 - 2*2^3 + 4*2^2 - 5 = -1
fmin(0) = - 5
fmax + fmin = -1 - 5 = -6
