kill(all)$

van=facebook.com/LearningCalculus$

f(x):=
abs
(
    abs(x^3-1)-
    abs(x^2-1)-
    abs(x  -1)-
    1
);

g(x):=x^3-x^2-x+2;

gp(x):=''(diff(g(x),x));

solve(gp(x)=0,x);

g(-1/3);