Synthetic division work with the coefficient of the given polynomial expression
We have
-15 -16 84 -17 -9 -15
and the divisor is:
x - ⁸/₅ = 0
x = ⁸/₅
Refer to the diagram below for the steps of synthetic division
Start by multiplying the first coefficient by the divisor, write the answer under the second coefficient, and then add the two values.
Repeat the steps until we use up all the remaining coefficients
The final values are the coefficients of the quotient and the last value is the reminder