So you know that P(x)= (x-3)Q(x)+ 2= (x+2)R(x)- 13. Then (x+2)P(x)= (x+2)(x-3)Q(x)+ 2(x+2) and (x-3)P(x)= (x+2)(x-3)R(x)- 13(x- 3). Subtracting the two equations, ((x+2)- (x- 3))P(x)= 5P(x)= (x+2)(x-3)(Q(x)- R(x))+ 15x- 35. P(x)= (x+2)(x-3)S(x)+ 3x- 7 where S(x) is (Q(x)- R(x))/5.