Chapter 1: Problem 16
Graph all solutions on a number line and provide the corresponding interval notation. ?2a+5>5
Short Answer
Expert verified
Graph: Open circle at 0, arrow to the right. Interval: \((0, \infty)\).
Step by step solution
01
Simplify the Inequality
Start by simplifying the inequality. Given: \[ 2a + 5 > 5 \] Subtract 5 from both sides to isolate the term with the variable:\[ 2a + 5 - 5 > 5 - 5 \] Which simplifies to:\[ 2a > 0 \]
02
Solve for the Variable
Next, solve for \( a \) by dividing both sides of the inequality by 2:\[ \frac{2a}{2} > \frac{0}{2} \] This simplifies to:\[ a > 0 \] This means any number greater than zero is a solution.
03
Graph the Solution on a Number Line
To graph the solution \( a > 0 \), draw a number line. Place an open circle on zero to indicate that zero is not included. Then draw a line or arrow extending to the right, reflecting that all numbers greater than zero are solutions.
04
Express in Interval Notation
Finally, express the solution \( a > 0 \) in interval notation. Since it includes all numbers greater than zero, the interval is:\( (0, \infty) \) The parenthesis indicates that zero is not included, and the infinity symbol indicates it goes infinitely large.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing on a Number Line
Graphing inequalities on a number line helps us visually represent the range of solutions for an inequality. It’s like creating a map for numbers that satisfy the given condition. Here's how to do it:
- Identify the inequality's condition, like if it’s greater than (>), less than (<), or includes equal to (≥ or ≤).
- Find the critical point(s) from the solved inequality. In the exercise, we found that the critical point is 0.
- Use a number line and mark the critical point. For inequalities without 'equal to', use an open circle. If the inequality includes 'equal to', use a closed circle.
- Draw an arrow or line extending from the circle in the direction specified by the inequality symbol. For example, for '> 0', draw an arrow extending to the right from zero.
Solving Inequalities
Solving inequalities is similar to solving equations, with some key differences. Here’s how to approach them:
- First, simplify the inequality by performing operations like addition, subtraction, multiplication, or division, as you would with an equation. For instance, we started with \( 2a + 5 > 5 \).
- Isolate the variable on one side of the inequality. Often, this involves getting rid of constants on the same side as the variable, as seen with \( 2a > 0 \).
- When dividing or multiplying both sides by a negative number, remember to flip the inequality sign. For example, if dividing by -1, '>' becomes '<'.
Interval Notation
Interval notation offers a concise way to express a range of solutions from an inequality. It is a handy tool to indicate which numbers are solutions without having to draw them. Here’s how it works:
- You use parentheses \( ( ) \) to show that endpoints are not included in the solution set, much like an open circle on a number line.
- Use brackets \( [ ] \) if the endpoints are included, akin to a closed circle.
- The two numbers in the notation signify the smallest and largest numbers in the solution set, respectively. For example, in the inequality \( a > 0 \), zero is not included, so we write \( (0, \infty) \).
- The infinity symbol (often written as \( \infty \)) indicates the solution continues indefinitely in a positive or negative direction.