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What is the Definition of the Solution of an Inequality?

Published in Inequality Solutions 3 mins read

A solution to an inequality is a value that, when substituted for the variable, makes the inequality statement true.

Understanding Inequality Solutions

When working with inequalities, you're not just looking for one specific number as a solution like you might with an equation. Instead, you're looking for a range of values that satisfy the inequality. A solution 'satisfies' the inequality meaning that substituting the solution value for the variable results in a true mathematical statement, according to our provided reference.

Key Characteristics:

  • Satisfies the Inequality: As stated in the reference, the solution will result in a true inequality statement when the value is substituted for the variable.
  • Multiple Solutions: Often, there isn't just one solution; there can be many or even infinitely many.
  • Number Line Representation: Solutions can often be represented as a range on a number line.
  • Verification: It's crucial to verify if a value is indeed a solution by substitution.

Examples

Let's look at a few examples:

  • Example 1: x > 3
    • Any number greater than 3 is a solution. For example, 4, 5, 3.1, and 100 are all solutions.
    • If you substituted 4 for x in x > 3, you’d get 4 > 3 which is true.
    • If you substituted 2 for x in x > 3, you’d get 2 > 3 which is false. So, 2 is not a solution for this inequality.
  • Example 2: y ≤ 5
    • Any number less than or equal to 5 is a solution. For instance, 5, 4, 0, and -20 are all solutions.
    • If you substituted 5 for y in y ≤ 5, you'd get 5 ≤ 5 which is true.
    • If you substituted 6 for y in y ≤ 5, you'd get 6 ≤ 5 which is false. Therefore, 6 is not a solution.
  • Example 3: 2a + 1 < 7
    • To solve this, we would first subtract 1 from both sides: 2a < 6.
    • Then, we divide both sides by 2: a < 3.
    • This means that any number less than 3 is a solution. For example, 2, 0, and -5 are all solutions.
    • If we substitute 2 for a in 2a + 1 < 7 we’d get 2(2) + 1 < 7 which simplifies to 5 < 7, which is true.
    • If we substitute 3 for a in 2a + 1 < 7 we'd get 2(3) + 1 < 7 which simplifies to 7 < 7, which is false, so 3 is not a solution.

Solution Techniques

  • Isolate the Variable: Use algebraic manipulations to get the variable alone on one side of the inequality sign. Remember to reverse the inequality sign if you multiply or divide by a negative number.
  • Test Values: Substitute values from the solution set into the original inequality to check that they satisfy it.
  • Graphical Representation: Represent the solution set on a number line to visualize the range of solutions.

Practical Implications

Understanding the solution of an inequality is useful in:

  • Determining range of values that satisfy constraints in real-world problems.
  • Analyzing data sets.
  • Setting conditions within computer programming.
  • Optimizing processes.

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