Re: Factorising expressions

You need to recognise that (4-x) = -(x - 4). Then the factorisation should be easy.

Re: Factorising expressions

Firstly there are no shortcuts and we should also not try and look for those without understanding the basic concept. There is no standard way of factorizing ll polynomials. For example be can factorize quadratics by splitting middle term, rearranging terms, making perfect square etc. for cubic polynomials we first try and find if the expression is a cube or not, we thereafter try and find the first linear factor by hit and trial using remainder theorem etc. i hope that helps you