Question 737605
Setting the pieces to perform synthetic division:


1___|___2____-1____3_____-1_____5
____|___.____2_____1_____4______3
___________________________________
________2____1_____4______3_____8



Check about two things in the method.  I choose the root being tested-for from the binomial divisor, which is the POSITIVE 1.  The first and second row elements are ADDED for obtaining the bottom row elements.


You could backtrack in advancement of method and compare results with regular polynomial division.