(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).