For any polynomial of degree n, we can always find a complete term of degree n by using the highest term and (n- 1) term according to the binomial theorem, and the result can be followed by a constant term, a quadratic term, a cubic term and so on. Up to item (n-2).

Especially, for cubic polynomials, in addition to the complete cubic term, the result can be followed by constant terms and linear terms.

Extended data:

Because the degree of polynomial is more than quadratic, it is not necessarily guaranteed that there is only a constant term after the complete n-power term after the n-power term. Therefore, it is impossible to simply match the completely flat formula about x for the quadratic integral equation, and then move the remaining constant term to the other side of the equal sign, and then square it, and the general formula for finding the root can be derived.

Solving quadratic or quadratic one-dimensional integral equations often requires a lot of ingenious transformations, and the complexity of both the solution process and the root formula is much higher than that of linear and quadratic equations.

Baidu encyclopedia-binomial theorem