Answer:
The number is 10
.
Step-by-step explanation:
(x+1)(x−3)(x−4)
=((x+1)(x−3))(x+−4)
=((x+1)(x−3))(x)+((x+1)(x−3))(−4)
=x3−2x2−3x−4x2+8x+12
=x3−6x2+5x+12