Hi,

Does anyone know a reasonably standard technique to factorise something like,

$\displaystyle x^4 + y^4 + 9x^2 + y^2 - 6x^3 + 2x^2y^2 - 6xy^2 - 4x = 0$

into:

$\displaystyle (x^2-4x+y^2) (x^2-2x+y^2+1) = 0$

i.e. when not given any other information (like one of the factors), how to recognise it can be factored, and do it etc