Chapter 1: Problem 121
Find the distance between the given numbers on a number line. 78 and -15
Short Answer
Expert verified
The distance is 93.
Step by step solution
01
Understanding the Problem
We are asked to find the distance between two numbers on a number line: 78 and -15. This means finding the absolute difference between these numbers.
02
Distance Formula on a Number Line
To find the distance between two points on a number line, we use the formula: \[ \text{Distance} = |a - b| \text{ or } |b - a| \]where \(a\) and \(b\) are the numbers given.
03
Substitute the Values
Substitute 78 for \(a\) and -15 for \(b\) into the distance formula: \[ \text{Distance} = |78 - (-15)| \]
04
Simplify the Expression
Simplify the expression inside the absolute value bars:\[ 78 - (-15) = 78 + 15 = 93 \]
05
Calculate the Absolute Value
Find the absolute value of the simplified expression. Since the absolute value of 93 is 93, we have:\[ \text{Distance} = |93| = 93 \]
06
Conclusion
The distance between 78 and -15 on a number line is 93.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Absolute Value
When talking about absolute value, think of it as the distance of a number from zero on a number line, regardless of direction. This means the absolute value of a number is always non-negative.
- Symbol: We use vertical bars to denote absolute value, like this: \(|a|\).
- Basic Example: For the number 5, the absolute value is \(|5| = 5\). For the number -5, it's also \(|-5| = 5\).
- Real-World Analogy: Imagine you're talking about the actual miles you walk to get somewhere, regardless of the direction you take. That's similar to absolute value.
Number Line
A number line is a straight line where each point corresponds to a real number. It's a powerful visual tool that helps us understand different numbers and their relationships.
- Zero at the Center: Typically, zero is in the center, with positive numbers to the right and negative numbers to the left.
- Spacing: Consistent intervals allow us to see the distance and values clearly. Each tick mark represents an equal magnitude away from neighboring numbers.
- Understanding Numbers: Use the number line to grasp how far apart numbers are, like 78 and -15 in our example. It clearly shows why their distance is calculated using absolute value.
Distance Formula
To determine the distance between two points on a number line, we use a simple yet efficient formula. This is crucial in various fields, including math and physics.
- Formula: The distance is calculated as \[ \text{Distance} = |a - b| \,\]/\[ \text{or} \ |b - a| \.\]
- Substitute Values: In exercises, substitute the given values into the formula for calculation. For example, with numbers 78 and -15, the formula becomes \[\text{Distance} = |78 - (-15)|.\]
- Simplification: Simplify inside the absolute value: \(|78 + 15| = 93\). Since 93 is already positive, the absolute value remains 93.
- Conclusion: The distance on the number line between these two points is \(|93| = 93\).