F'(X) = 12X^2 - 2
12X^2 - 2 = 0
2(6X^2 - 1) = 0
6X^2 = 1
X^2 = 1\6
X = V (1\6)
F(X) = 4X^3 - 2X - 40 = 1\54 - 1\3 - 40 = 1\54 - 18\54 - 40 = - 17\54 - 40 = - 40 17\54
F'(X) = 12X^2 - 2
12X^2 - 2 = 0
2(6X^2 - 1) = 0
6X^2 = 1
X^2 = 1\6
X = V (1\6)
F(X) = 4X^3 - 2X - 40 = 1\54 - 1\3 - 40 = 1\54 - 18\54 - 40 = - 17\54 - 40 = - 40 17\54