Answer:
steps below
Step-by-step explanation:
f(x) = x⁷ – 6x⁶ + 8x⁵
f'(x) = 7x⁶ - 36x⁵ + 40x⁴
= x⁴ (7x² - 36x + 40) ... (1)
Critical point (x,y): x = 0 , x = (36 ± √(-36)²-4*7*40) / (2*7) = (18±2√11) / 7
x = 0 or x = 3.5 or x = 1.6
plug into (1): y = 0 , y = -394.3 , y = 10.1
extreme : maximum (1.6 , 10.1) minimum (3.5 , -394.3) ... turning points
x⁷ – 6x⁶ + 8x⁵ = x⁵ (x² - 6x + 8) = x⁵ (x-2) (x-4) =0
real zeros: x = 0, x=2, x=4
