Firstly, we need to understand what is meant by synthetic division.
In synthetic division, we write out coefficients of the divisor.
The coefficients of the divisor are;
3 , 6 , 2 , 9 , 10
Now, lets take a look at the term which we would be dividing with. We simply set the term which is x + 2 to 0
This gives x + 2 = 0
and thus, x = -2
This is the value w