Simple for you guys i guess, But tough for me - Guess im just thick! [itex]x^4 +Ax^3 + 5x^2 + x + 3 = (x^2 +4)(X^2 -x +B) +Cx +D[/itex] I get: [itex]x^4 +Ax^3 + 5x^2 + x + 3 = X^4 -x^3 - 4x^2 + Bx^2 - 4x + 4B + Cx + D[/itex] Now, I think i need to simplify this more because i can't compare co-efficients can i? Can someone run me through the further simplifications? Maybe [itex]Bx^2 + 4x^2[/itex] into [itex](4+B)X^2[/itex] ? Is this wise and possible? What else? Need to learn simplification better, Finding my basic maths is poor so Alevel is tough!