1, inequality solving methods and skills to solve absolute value problems (simplification, evaluation, equations, inequalities, functions), and turn problems with absolute values into problems without absolute values. The specific transformation methods are as follows:

(1) Classification discussion method: according to the positive, zero and negative scores of numbers or formulas in absolute value symbols, the absolute value is removed. ?

(2) Zero-paragraph discussion method: it is suitable for the case that multiple absolute values contain one letter. ?

(3) Bilateral flattening method: it is suitable for equations or inequalities with non-negative edges.

2. The concept of inequality generally uses a pure greater than sign ">" and less than sign ".

An inequality represented by "≦" is also an inequality.

Among them, the common area of analytical expressions on both sides is called inequality area. Algebraic expression inequality: both sides of algebraic expression inequality are algebraic expressions (that is, the unknown is not in the denominator).