Fx=x^3/3+x^2-3x+9 решите уравнение f'(x)=0

F(x) = x^3/3 + x^2 - 3x + 9
f'(x) = 1/3 * 3x^2 + 2x - 3 = x^2 + 2x - 3
x^2 + 2x - 3 = 0
D = b^2 - 4ac = 4 - 4*(-3) = 4 + 12 = 16
x1 = (-2 + 4)/2 = 2/2 = 1
x2 = (-2 - 4)/2 = -6/2 = -3

ответ: -3; 1.