Suppose `a ,b ,c in I` such that the greatest common divisor fo `x^2+a x+ba n d x^2+b x+ci s(x+1)` and the least common ultiple of `x^2+a x+ba n dx^2+b x+c` is `(x^3-4x^2+x+6)dot` Then the value of `|a+b+c|` is equal to ___________.