I think you can still use remainder theorem?
Factorise the divisor into
Using remainder theorem in the original polynomial, we know that:
![](https://latex.codecogs.com/png.latex?\bg_white P(0)=3)
and
Using the polynomial in division form:
We know that
![](https://latex.codecogs.com/png.latex?\bg_white P(-1)=5)
, so sub it into the divison form to get:
(
![](https://latex.codecogs.com/png.latex?\bg_white P(0)=3)
does not work since
![](https://latex.codecogs.com/png.latex?\bg_white x=0)
which does not enable you to solve for a)