Cross method: the left multiplication of cross is equal to the coefficient of quadratic term, the right multiplication is equal to the constant term, and the cross multiplication is equal to the coefficient of linear term. Cross multiplication can decompose some quadratic trinomials. The key of this method is to decompose quadratic coefficient A into two factors A 1, product a 1, a2, constant term C into two factors c 1, c2 times C2 product C 1, so that c 1, C2+A2c/kloc-0.

Methods Pay attention to observation, try and realize that it is the inverse of binomial multiplication in essence.

When the first coefficient is not 1, it is usually necessary to

Process.

To test many times, be sure to pay attention to the sign of each coefficient. Grouping decomposition method: properly group the items, so that the decomposition factors are grouped first, and then decompose the factors between groups.

Parentheses: there is a "+"sign before parentheses, and all items in parentheses remain unchanged; There is a "-"sign in front of brackets, and all items in brackets will change their symbols. When there are many terms in polynomials, polynomials can be grouped reasonably to achieve the purpose of smooth decomposition. Of course, other sub-methods can also be integrated, and the grouping method is not necessarily unique.

Help you! Hope to adopt.