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Ch. P - Fundamental Concepts of Algebra
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 1, Problem 47

Add or subtract as indicated. 2/5x − (x+1)/4x

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1
Identify the expression to simplify: \(\frac{2}{5x} - \frac{x+1}{4x}\).
Find the least common denominator (LCD) of the two fractions. Since the denominators are \$5x\( and \)4x\(, the LCD is \)20x$.
Rewrite each fraction with the common denominator \$20x$: multiply numerator and denominator of \(\frac{2}{5x}\) by 4, and multiply numerator and denominator of \(\frac{x+1}{4x}\) by 5.
Express the subtraction with the common denominator: \(\frac{2 \times 4}{20x} - \frac{(x+1) \times 5}{20x}\), which simplifies to \(\frac{8}{20x} - \frac{5(x+1)}{20x}\).
Combine the numerators over the common denominator: \(\frac{8 - 5(x+1)}{20x}\), then simplify the numerator by distributing 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.

Like Terms and Variable Expressions

Understanding how to identify and combine like terms is essential when working with algebraic expressions. Terms with the same variable and exponent can be added or subtracted directly, while unlike terms must be handled separately.
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Finding the Least Common Denominator (LCD)

The least common denominator is the smallest expression that both denominators divide into evenly. Identifying the LCD allows you to rewrite each fraction with a common denominator, enabling addition or subtraction of the numerators.
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