I have the equation $$x^3-8x^2+30x-20=0$$ let's call the roots $a,b,c$
It's easy to find the equation with roots $(a+2)(b+2)(c+2)$ these are the steps in my books
so the equation is $$ aX^3+ bX^2 + cX + D = 0 $$ $$ x^3 -14x^2 +74x -120 = 0$$
my problem is, I can't understand why divide by $-2$ not $2$ how do I do this division with long division? like what am I dividing by if the symbols were here?!