A statement involving a variable and a sign of inequality (viz. < , ≤ , > or ≥) is called an inequality
. A statement of inequality between two expressions consisting of a single variable, say x, of highest power 1, is called a linear inequality in one variable
. It is ussually written in any of the following forms:
where a ≠ 0;
Linear inequalities are solved much the same way as linear equations are solved, with one important exception: when multiplying or dividing both sides of an inequality by a negative number, the inequality sign must be reversed.