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Compound Inequality Calculator

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How to Solve Compound Inequalities with Steps and Examples

Compound Inequality Calculator

Example: 2x + 3 < 9 and x > 1

What is Compound Inequality Calculator?

A Compound Inequality Calculator is a smart algebra tool that solves compound inequalities—mathematical statements that combine two or more inequalities joined by "and" or "or". It instantly interprets, solves, and explains the solution set using interval notation and number line visuals. These calculators make it easy for students, parents, and teachers to check their compound inequality problems, see detailed solution steps, and visualize the answer. Whether you're tackling homework, reviewing for exams, or learning algebraic concepts, this powerful calculator provides an interactive way to master compound inequalities with step-by-step guidance.


Formula or Logic Behind Compound Inequality Calculator

The logic behind the Compound Inequality Calculator is based on these core principles:

  • If joined by "and": Find the intersection (common solutions) of individual inequalities (e.g., a < x < b means x is between a and b).
  • If joined by "or": Find the union (all solutions from either inequality).
  • Each inequality is solved as a linear inequality for x (e.g., ax + b < c).
  • The final answer is presented in interval notation and on a number line for clear understanding.
This makes it much easier to understand and solve compound inequalities with detailed steps and graphical support.


Common Compound Inequality Examples and Solutions

Compound Inequality Solution Steps Interval Notation
2x + 3 < 9 and x > 1 1. 2x + 3 < 9 ⇒ 2x < 6 ⇒ x < 3
2. x > 1
Intersection: 1 < x < 3
(1, 3)
x - 2 > 0 or x + 5 < 3 1. x - 2 > 0 ⇒ x > 2
2. x + 5 < 3 ⇒ x < -2
Union: x < -2 or x > 2
(-∞, -2) ∪ (2, ∞)
3x + 5 ≥ 2 and x - 4 ≤ 6 1. 3x + 5 ≥ 2 ⇒ 3x ≥ -3 ⇒ x ≥ -1
2. x - 4 ≤ 6 ⇒ x ≤ 10
Intersection: -1 ≤ x ≤ 10
[-1, 10]
2x - 7 < -3 or x > 5 1. 2x - 7 < -3 ⇒ 2x < 4 ⇒ x < 2
2. x > 5
Union: x < 2 or x > 5
(-∞, 2) ∪ (5, ∞)

Steps to Use the Compound Inequality Calculator

  • Enter your compound inequality expression in the input box (for example, 2x + 3 < 9 and x > 1).
  • Click on the 'Calculate' button.
  • Get the detailed solution, including interval notation and number line visualization.

Why Use Vedantu’s Compound Inequality Calculator?

Vedantu’s Compound Inequality Calculator is designed by certified Maths educators for the latest CBSE and NCERT curriculum, providing accuracy-verified results. It’s easy to use, fully mobile-friendly, and displays instant step-by-step explanations. Trusted by millions of Indian students and recommended by teachers, this tool simplifies algebra – making concepts clear for school and competitive exams.


Real-life Applications of Compound Inequality Calculator

The compound inequality calculator finds use beyond academics:

  • Specifying safe temperature ranges in science labs or medicine storage: e.g., 2°C < T < 8°C
  • Defining speed limits: 40 ≤ speed ≤ 60 km/h
  • Testing qualification marks in competitive exams: 50 < score ≤ 80
  • Verifying allowed concentration ranges in chemistry experiments
  • Auditing age groups for eligibility: Age ≥ 18 and Age ≤ 25
  • Many daily situations involving limits and boundaries
With this calculator, students and professionals can quickly convert real-world conditions into precise algebraic intervals.


Explore other helpful math tools at Vedantu: HCF Calculator, Prime Numbers, Factors of Numbers, and a full guide to Algebra Topics. Simplify your math journey with step-by-step explanations and trusted resources.

FAQs on Compound Inequality Calculator

1. What is a compound inequality?

A compound inequality is a mathematical statement that combines two or more inequalities using the words "and" or "or." It represents a range of values that satisfy both (in the case of "and") or at least one (in the case of "or") of the inequalities. Understanding compound inequalities is crucial for solving various real-world problems and mastering algebra.

2. How do I solve a compound inequality with "and"?

To solve a compound inequality joined by "and," you need to find the values that satisfy *both* inequalities simultaneously. This means the solution will be the intersection of the solution sets of each individual inequality. Graphing the inequalities on a number line can be helpful to visualize the overlapping region, which represents the solution. The solution set will be the values common to both inequalities.

3. How do I solve a compound inequality with "or"?

When solving compound inequalities joined by "or," you are looking for values that satisfy *at least one* of the inequalities. The solution is the union of the solution sets of the individual inequalities. This means you combine all the values from both solutions. Graphically, this includes all parts of the number line covered by either inequality.

4. What is interval notation for compound inequalities?

Interval notation provides a concise way to represent the solution set of a compound inequality. For example, if the solution is all values between 2 and 5 (inclusive), the interval notation would be [2, 5]. Parentheses ( ) indicate that the endpoint is not included, while brackets [ ] indicate inclusion. For inequalities with solutions extending to infinity, we use ∞ (positive infinity) or -∞ (negative infinity). For instance, x > 3 would be written as (3, ∞).

5. How do I graph a compound inequality on a number line?

Graphing on a number line visually represents the solution set. For "and" inequalities, you'll see an overlapping section. For "or" inequalities, you'll see two separate sections, or potentially the entire number line if the inequalities cover everything. Use closed circles (•) to include endpoints, and open circles (o) to exclude them. Shade the region(s) representing the solution set.

6. What are some real-world applications of compound inequalities?

Compound inequalities are used in various real-world scenarios. For instance:
Temperature ranges: Maintaining a temperature between a minimum and maximum value (e.g., 20°C to 25°C).
Speed limits: Driving within a specified speed range.
Budgeting: Staying within a spending limit, yet ensuring you're spending enough to cover essential expenses.
Manufacturing tolerances: Producing items where dimensions must fall within a precise range.

7. What is the difference between a compound inequality and a system of inequalities?

While both involve multiple inequalities, there's a key distinction. A compound inequality combines two or more inequalities using "and" or "or," resulting in a single solution set. A system of inequalities involves multiple inequalities that must be solved simultaneously; the solution is where *all* inequalities are satisfied, representing the intersection of the solution sets.

8. How do I write a compound inequality from a word problem?

Carefully read the problem to identify the variables and conditions. Translate the words into mathematical symbols. For example, "x is greater than 5 and less than 10" translates to 5 < x < 10 (an "and" inequality). Phrases like "at least" or "at most" often indicate inequalities.

9. What are some common mistakes students make when solving compound inequalities?

Common mistakes include:
• Misinterpreting "and" and "or" conditions.
• Incorrectly applying the rules when multiplying or dividing by a negative number.
• Forgetting to reverse the inequality symbol when multiplying or dividing by a negative number.
• Failing to graph the solutions accurately on a number line. Careful attention to detail is crucial.

10. Can I use this calculator to solve absolute value inequalities?

This particular calculator is designed for compound inequalities that are already expressed without absolute values. Absolute value inequalities require a different approach to solve, which involves considering both positive and negative cases. A dedicated absolute value inequality calculator would be more appropriate for those problems.

11. How do I represent the solution of a compound inequality using set builder notation?

Set builder notation describes a set using a rule that defines the elements. For example, if the solution to a compound inequality is all numbers between 2 and 7 (inclusive), you would write it as {x | 2 ≤ x ≤ 7}. This reads as "the set of all x such that x is greater than or equal to 2 and less than or equal to 7."