synthetic division

Jul 2010
614
5
Hi; In synthetic division why do we change the sign of the divisor? say I have to divide a polynomial by (x - 2) why do I need to use +2?Thanks.
 

HallsofIvy

MHF Helper
Apr 2005
20,249
7,909
In "ordinary" division, we are dividing by x- a and subtract. In synthetic division we use "a" rather than "-a" and add rather than subtract.