Idioma de origen: Inglés
Q: I had "Factoring" chosen and 12x + 6 entered. The UMS replied with "This expression may not be factored (with rational coefficients)". But, look, in 6·(2x + 1) all the coefficients are rational.
A: The software treats the "Factoring" term as "product expansion into two factors of non-zero degree with rational coefficients". That is the reason why the factorization was not done, despite the fact, that the example is proper.