I'm practicing for an entry exam to a foreign university and one of the requirements is understanding
"Algebraic equations - factoring cubic and degree four expressions"
Could someone give me an example of this? I feel like the english is off. I have not had an issue understanding any of the previous questions.. thanks.
factor $$ x^4 + 9x^2 + 4x + 21 $$ The central parts are the rational roots theorem, how do divide out if there is a root, and the Gauss theorem on content, which says that a polynomial with integer coefficients that factors with rational coefficients ALSO factors with all integer coefficients.