Chapter 1 One-dimensional linear inequalities and one-dimensional linear inequalities 1. Generally speaking, formulas connected by the symbol ""(or "≥") are called inequalities. The value of the unknown quantity that can make the inequality hold is called the solution of the inequality. The solution of inequality is not unique. All the inequalities are liberated together to form the solution set of inequalities. The process of finding the solution set of inequality is called solving inequality. An inequality group composed of several linear inequality groups is called the solution set of the linear inequality group: the common part of the solution set of each inequality in the linear inequality group. The basic property of equation 1: Add (or subtract) the same number or algebraic expression on both sides of the equation, and the result is still an equation. Basic property 2: Multiply or divide the same numbers on both sides of the equation (the divisor is not 0), and the result is still an equation. Second, the basic properties of inequality 1: the addition (or subtraction) of the same algebraic expression on both sides of inequality is not equal. ) property 2: both sides of the inequality are multiplied (or divided) by the same positive number, and the direction of the inequality remains unchanged. Property 3: When both sides of the inequality are multiplied by (or divided by) the same negative number, the direction of the inequality changes. Basic properties of inequality