Your Flashcards are Ready!
15 Flashcards in this deck.
Topic 2/3
15 Flashcards in this deck.
Inequalities are mathematical statements that show the relationship between two expressions that are not equal. Unlike equations, which use the equal sign ($=$), inequalities use symbols such as greater than ($>$), less than ($<$), greater than or equal to ($\geq$), and less than or equal to ($\leq$). These symbols indicate that one expression is larger or smaller than the other, rather than being equal.
A one-step inequality is an inequality that can be solved using a single algebraic operation. The goal is to isolate the variable on one side of the inequality symbol to determine its range of possible values.
Solving one-step inequalities involves performing the inverse operation to both sides of the inequality to isolate the variable. The process is similar to solving one-step equations but with additional considerations, especially when multiplying or dividing by negative numbers.
If a variable is being added or subtracted by a number, the inverse operation is used to isolate the variable.
Example: Solve $x + 5 > 12$
Solution:
If a variable is being multiplied or divided by a number, the inverse operation is used. It's crucial to remember that when multiplying or dividing both sides of an inequality by a negative number, the inequality sign reverses direction.
Example: Solve $-3x \leq 9$
Solution:
Once the inequality is solved, the solution can be represented on a number line to visually illustrate the range of possible values for the variable.
Example: Represent $x > 7$ on a number line.
Solution:
While focused on one-step inequalities, understanding compound inequalities is beneficial as they involve two inequalities combined into one statement, such as $a < x < b$. This concept builds on one-step inequalities and is useful for more complex problem-solving.
One-step inequalities are applied in various real-life scenarios, including budgeting, where one might need to determine the range of possible expenses, or in engineering, where tolerances are established within certain limits.
Example 1: Solve $5 - x \leq 12$
Solution:
Example 2: Solve $\frac{x}{4} > 3$
Solution:
Graphing one-step inequalities on a number line provides a visual understanding of the solution set.
Example: Graph $x \leq 5$
Solution:
Applying one-step inequalities to real-world problems reinforces understanding and demonstrates practical utility.
Example: A student has at most $20 to spend on textbooks. If each textbook costs $x, write an inequality to represent this situation and solve for $x$.
Solution:
Being able to translate verbal statements into mathematical inequalities is crucial for solving real-life problems.
Example: "Maria needs at least 50 minutes to complete her homework." Translate and solve for the time $t$.
Solution:
Always verify the solution by substituting it back into the original inequality to ensure its accuracy.
Example: Solve and check $x - 4 < 10$
Solution:
Understanding the difference between inequalities and equations is fundamental. While equations represent exact values, inequalities represent a range of possible values.
Example:
Engaging with interactive tools and practice problems enhances comprehension and retention of solving one-step inequalities.
Resources:
Aspect | One-Step Inequalities | One-Step Equations |
Definition | Mathematical statements showing a range of possible values using inequality symbols. | Mathematical statements showing equality between two expressions using the equal sign. |
Solution | A range of values satisfying the inequality. | A unique value that makes the equation true. |
Graphical Representation | Shaded regions on a number line indicating all possible solutions. | A single point on a number line representing the solution. |
Operations Involved | Addition, subtraction, multiplication, division, with consideration for reversing the inequality sign. | Addition, subtraction, multiplication, division, without changing any signs. |
Example | $x + 3 > 7$ | $x + 3 = 7$ |
Solution Set | $x > 4$ | $x = 4$ |
Use the mnemonic **"Flip the sign when negative"** to remember to reverse the inequality sign when you multiply or divide by a negative number. Additionally, always double-check your solutions by plugging them back into the original inequality to ensure they satisfy the condition.
Did you know that inequalities play a crucial role in optimization problems in various fields such as economics and engineering? For instance, businesses use inequalities to determine profit margins and minimize costs. Additionally, in computer science, inequalities are fundamental in algorithms that ensure optimal performance and resource management.
Students often forget to reverse the inequality sign when multiplying or dividing by a negative number. For example, when solving $-2x > 4$, the correct approach is to divide by -2 and reverse the sign, resulting in $x < -2$. Forgetting to reverse the sign would incorrectly suggest $x > -2$.