Chapter 1: Problem 45
Perform the following operations with real numbers. $$-\frac{2}{3}-\frac{7}{9}$$
Short Answer
Expert verified
The result is \(-\frac{13}{9}\).
Step by step solution
01
Find a Common Denominator
To perform the operation with fractions, we need a common denominator. The denominators in the fractions are 3 and 9. The least common multiple of 3 and 9 is 9, so that will be our common denominator.
02
Convert the First Fraction
Convert \(-\frac{2}{3}\) to a fraction with denominator 9. Multiply both the numerator and the denominator by 3 to get: \(-\frac{2\times3}{3\times3} = -\frac{6}{9}\).
03
Perform the Subtraction
Now that both fractions have the same denominator, subtract the fractions: \(-\frac{6}{9} - \frac{7}{9} = \frac{-6 - 7}{9} = \frac{-13}{9}\).
04
Simplify if Necessary
The fraction \(-\frac{13}{9}\) is already in its simplest form, as 13 is a prime number and not divisible by 9. Therefore, no further simplification is necessary.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Fractions
Fractions represent parts of a whole. They consist of a numerator and a denominator.
- The numerator is the top number and indicates how many parts you have.
- The denominator is the bottom number and shows into how many parts the whole is divided.
Common Denominator
Finding a common denominator is essential for performing operations such as addition and subtraction on fractions. The common denominator is a shared multiple of the original denominators of the fractions. For the fractions \(-\frac{2}{3}\) and \(-\frac{7}{9}\), you first identify the denominators, which are 3 and 9. The least common multiple of 3 and 9 is 9, making it the ideal common denominator.
- Selecting the least common multiple helps minimize the size of the numbers you work with, simplifying calculations.
- Converting fractions to have this common denominator is crucial for accurately performing mathematical operations.
Subtraction
Subtracting fractions requires them to share the same denominator. Once the fractions \(-\frac{6}{9}\) and \(-\frac{7}{9}\) have a common denominator, subtracting the fractions becomes straightforward. To subtract, keep the denominator, and subtract the numerators.
- The calculation becomes: \(-\frac{6}{9} - \frac{7}{9} = \frac{-6 - 7}{9}.\)
- Subtracting the numerators, we get \(-13\).
- The result is \(-\frac{13}{9}\).
Simplification
Simplifying fractions means reducing them to their simplest form. A fraction is in its simplest form when the numerator and the denominator have no common factors other than 1. In the result from our subtraction, \(-\frac{13}{9}\), both 13 and 9 are analyzed.
- The number 13 is a prime number, meaning it can only be divided by 1 and itself, and it shares no common factors with 9 other than 1.
- This means \(-\frac{13}{9}\) is already in its simplest form.