Решите уравнение: f штрих(x)=0 a) f(x)=x^3+3x^2+3x+1 b) f(x)=x^3-6x^2+12x-1

#1
3x^2 + 6x + 3 = 0 
D = 36 - 36 = 0 
x = - b/2a = - 6/6 = - 1

#2
3x^2 - 12x^2 + 12 = 0 /:3
x^2 - 4x + 4 = 0 
(x - 2)^2 = 0 
x - 2 =  0
x = 2