Hello,

Let y be the common remainder. y will be a constant, because you divide by a polynom of degree 1.

If you develop , you get, by identification :

(i leave you the right to do the calculus )

In the same way,

Hence 2c'=-c.

With (1) and (2), we can state that 2(p+8)=-(p-1)

And then, just solve for p