Exercise. 7.3: Solving linear Inequalities

Exercise. 7.3: Solving linear Inequalities: Linear inequalities are mathematical statements that compare two expressions using inequality symbols instead of an equal sign. These expressions can involve:

  • Numbers: Simple comparisons like 2 < 5 or 8 ≥ 3.
  • Variables: Symbols representing unknown quantities, for example, x > y or 2w ≤ -1.
  • Combinations: Mix of numbers and variables, like 3x + 2 < 10 or y – 5 ≥ 2x.

Key points about linear inequalities:

  • Structure: They look similar to linear equations, but with an inequality symbol (<, >, ≤, ≥, ≠) replacing the equal sign (=).
  • Examples: 3x – 1 > 8, y ≤ 4, -2a + 5 < 1.
  • Comparison Operators:
    • < (less than)
    • > (greater than)
    • ≤ (less than or equal to)
    • ≥ (greater than or equal to)
    • ≠ (not equal to) (less common in linear inequalities)

Think of them as expressing relationships like “greater than,” “less than,” and so on, instead of stating exact equalities. Exercise. 7.3:

These inequalities allow us to represent ranges of values that satisfy the comparison. Solving a linear inequality involves finding all those values for the variable(s) that make the statement true.

Understanding linear inequalities is foundational in various areas of mathematics like:

  • Problem-solving: Representing real-world scenarios involving limitations or constraints.
  • Modeling: Making mathematical models of situations with restrictions or boundaries.
  • Optimization: Finding solutions that maximize or minimize something within defined limits. Exercise. 7.3:
Exercise. 7.3: Solving linear Inequalities
  • Linear inequalities are mathematical expressions that involve linear equations and the use of inequality symbols such as < (less than), > (greater than), ≤ (less than or equal to), and ≥ (greater than or equal to).
  • These inequalities are essential in representing relationships between variables in a wide range of mathematical models, applications, and real-world scenarios.
  • The general form of a linear inequality in one variable is ax+b<c, where a, b, and c are constants, and x is the variable. In two variables, the general form is ax+by<c, where a, b, and c are constants, and x and y are the variables.
  • The same pattern extends to inequalities involving more variables. Linear inequalities can be graphically represented on a coordinate plane. The solution to a linear inequality is the set of all points (or ordered pairs, in the case of two variables) that satisfy the inequality.The boundary line of the inequality separates the coordinate plane into two regions: one where the inequality is true and another where it is false.
  • The choice of shading either the region above or below the boundary line depends on the inequality symbol.When solving systems of linear inequalities, the solution is often represented by the overlapping region of the individual solutions to each inequality. This overlapping region satisfies all the given conditions simultaneously.Linear inequalities are prevalent in various fields such as economics, optimization problems, physics, and engineering.
  • In economics, for example, they can represent constraints on resources or conditions for profit. In optimization problems, linear inequalities are used to find the maximum or minimum values of a function subject to certain constraints.
  • .Solving linear inequalities involves manipulating the inequalities through operations like addition, subtraction, multiplication, and division, while maintaining the direction of the inequality. The goal is to isolate the variable on one side of the inequality to determine the valid range of values.

Exercise. 7.3: Solving linear Inequalities

Questions & Answers

1. What are linear inequalities?

Answer: Linear inequalities are mathematical statements that compare two expressions using inequality symbols like <, >, , , instead of an equal sign, and can involve numbers, variables, or a combination of both.

2. Can you give examples of linear inequalities?

Answer: Sure, here are some examples:
2x + 1 < 5 (variable and numbers)
y – 3 ≥ 7 (variable and number)
5 < x (number and variable)

3. What are the different types of inequality symbols used?

Answer: The most common inequality symbols are:
< (less than)
> (greater than)
 (less than or equal to)
 (greater than or equal to)
 (not equal to) (less common in linear inequalities)

4. What does it mean to “solve” a linear inequality?

Answer: Solving a linear inequality means finding all the values for the variable(s) that make the inequality statement true. In other words, it involves finding the range of values that satisfy the comparison.

5. How are linear inequalities used in real-world applications?

Answer: Linear inequalities have various applications, such as:
Modeling limitations or constraints: Representing situations with boundaries or restrictions, like resource limitations or time constraints.
Optimization problems: Finding the minimum or maximum value of something within defined limits, like maximizing profit while staying within a budget.
Decision-making: Analyzing different scenarios based on various conditions and restrictions.

6. What are some additional things to know about linear inequalities?

Answer: While solving, be cautious when manipulating the inequality sign. Flipping the inequality sign requires reversing the direction of the inequality symbol. Additionally, linear inequalities can be graphed on a number line, visually depicting the solution set.


In conclusion, linear inequalities play a crucial role in mathematics and real-world applications by providing a powerful tool to represent relationships between variables. Exercise. 7.3:

 Whether in the context of algebraic equations, geometric interpretations, or practical problem-solving, linear inequalities offer a versatile framework for analyzing and understanding various scenarios.

 They allow us to express constraints, make predictions, and formulate decision-making criteria in diverse fields such as economics, engineering, and social sciences.

The ability to manipulate and solve linear inequalities equips individuals with essential problem-solving skills and a deeper comprehension of mathematical concepts.

As we navigate through the complexities of quantitative relationships, the understanding of linear inequalities remains fundamental, contributing to a broader proficiency in mathematical literacy and analytical thinking. Exercise. 7.3:

In conclusion, linear inequalities offer a powerful tool to represent and analyze situations involving comparisons or relationships between quantities. They go beyond simple equalities, allowing us to explore ranges of values that satisfy specific conditions.

Understanding linear inequalities is crucial in various fields, including problem-solving, modeling, and optimization. These inequalities help us represent constraints, find best outcomes within limitations, and make informed decisions based on various conditions. Exercise. 7.3:

Whether you’re studying mathematics, economics, engineering, or related fields, mastering linear inequalities unlocks a valuable tool for understanding and analyzing various phenomena in the world around you.

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Exercise # 7.3

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