# Elementary algebra -inequalities

In mathematics, inequalities are statements that describe the relationship between two expressions, indicating that one expression is greater than, less than, greater than or equal to, less than or equal to, or not equal to the other expression. Inequalities are used to compare quantities and establish constraints or bounds on variables.

The symbols commonly used to represent inequalities are as follows:

1. Greater than: “>
2. Less than: “<
3. Greater than or equal to: “>=
4. Less than or equal to: “<=
5. Not equal to: “” or “<>

Here are some key points to understand about inequalities:

1. Representation of Relations: Inequalities allow us to represent various relationships between quantities. For example, “x > 5” means that the value of “x” is greater than 5, while “y ≤ 10” indicates that the value of “y” is less than or equal to 10.
2. Interval Notation: Inequalities are often used to express intervals of real numbers. For instance, “3 < x ≤ 7” denotes that “x” lies in the open interval (3, 7] (inclusive of 7 and exclusive of 3).
3. Solving Inequalities: Solving an inequality involves finding the possible values of the variable that satisfy the given inequality. The solution may be expressed as a range or interval of valid values for the variable.
4. Properties: Inequalities follow similar properties to those of equations, such as the addition, subtraction, multiplication, and division properties. However, when multiplying or dividing by a negative number, the direction of the inequality sign is reversed. For example, given that 3 < 7 we can multiply both sides by -2 to obtain -6 > -14 which is also true.
5. Graphical Representation: Inequalities can be graphically represented on a number line or in the coordinate plane. For example, the inequality “x > 2” corresponds to all points to the right of 2 on the number line.
6. Systems of Inequalities: In many real-world problems, multiple inequalities may need to be considered simultaneously. This leads to the concept of systems of inequalities, where the solution is the set of values that satisfy all the given inequalities simultaneously.

Inequalities play a crucial role in various mathematical concepts, such as optimization, calculus, linear programming, and real analysis. They are also widely used in fields like economics, engineering, and sciences to model and analyze a range of situations where quantities are compared and constrained.

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