Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
0. Review of Algebra
Polynomials Intro
Problem 56c
Textbook Question
In Exercises 33–68, add or subtract as indicated. 3x/(x−3) − (x+4)/(x+2)
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1
Identify the least common denominator (LCD) for the fractions. The denominators are \(x-3\) and \(x+2\), so the LCD is \((x-3)(x+2)\).
Rewrite each fraction with the LCD as the new denominator. Multiply the numerator and denominator of the first fraction by \(x+2\) and the second fraction by \(x-3\).
The first fraction becomes \(\frac{3x(x+2)}{(x-3)(x+2)}\) and the second fraction becomes \(\frac{(x+4)(x-3)}{(x-3)(x+2)}\).
Subtract the second fraction from the first by combining the numerators over the common denominator: \(\frac{3x(x+2) - (x+4)(x-3)}{(x-3)(x+2)}\).
Simplify the expression in the numerator by expanding and combining like terms.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Rational Expressions
Rational expressions are fractions where the numerator and the denominator are polynomials. Understanding how to manipulate these expressions is crucial for performing operations like addition and subtraction. In this case, the expressions 3x/(x−3) and (x+4)/(x+2) are rational expressions that need to be combined.
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Common Denominator
To add or subtract rational expressions, it is essential to find a common denominator. The common denominator is the least common multiple (LCM) of the individual denominators. For the given expressions, the common denominator would be the product of (x−3) and (x+2), allowing for the expressions to be combined correctly.
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Simplifying Expressions
After performing the addition or subtraction of rational expressions, the result often needs to be simplified. This involves factoring the numerator and denominator, canceling any common factors, and rewriting the expression in its simplest form. Simplifying helps in understanding the behavior of the expression and makes it easier to analyze.
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