p(x) = x^3 - 6x^2 + 11x -13=(x-c)³+a(x-c)+b
=x³-2x²c+xc²-cx²+2xc²-c³+ax-ac+b
=x³-3cx²+3xc²+b+ax-c³
equate coefficients:
-6=-3c
c=2
-13=b-2³
b=-5
3c²+a=12+a=11
a=-1
p(x) = x^3 - 6x^2 + 11x -13
=(x-2)³-(x-2)-5
=(x-2)³-x-3
Sum of roots: A+B=0
ABC=3
-B²C=3
B²=-3\C
so two of the roots are not...