How to divide synthetically x^4-8x^3+26x^2-40x+21=0 by 2-i square root 3

Question

There are four possible roots, I need to know how to sythen

Answer 1

(x-3)(x-1)(x^2-4x+7)

Now,x=3,1

x^2-4x+7=0

Now apply Acharyas Formulae To have complex root of x Where one is 

2-i square root 3

i^2=-1

i=Root(-1)