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Simplify each complex fraction. See Examples 1 and \(2 .\) $$ \frac{\frac{5}{a+2}-\frac{1}{a-2}}{\frac{3}{2+a}+\frac{6}{2-a}} $$

Short Answer

Expert verified
The complex fraction simplifies to \( -\frac{4(a-3)}{3(a+6)} \).

Step by step solution

01

Identify the Main Fraction

The given expression is a complex fraction, which is a fraction where the numerator and/or the denominator contain fractions themselves. Here, the main fraction is \( \frac{\frac{5}{a+2}-\frac{1}{a-2}}{\frac{3}{2+a}+\frac{6}{2-a}} \).
02

Simplify the Denominator Factor First

Notice that \( 2+a \) and \( 2-a \) are in the denominator of the two fractions that are being added. First, rewrite \( \frac{6}{2-a} \) as \( \frac{-6}{a-2} \), since \( 2-a = -(a-2) \). The expression becomes \( \frac{3}{2+a} - \frac{6}{a-2} \).
03

Find the Common Denominator in the Denominator Part

For \( \frac{3}{2+a} - \frac{6}{a-2} \), find a common denominator, which is \((a+2)(a-2)\). This makes it easier to combine the fractions. Rewrite the terms as \( \frac{3(a-2)}{(a+2)(a-2)} \) and \( \frac{-6(a+2)}{(a+2)(a-2)} \).
04

Combine the Fractions in the Denominator

Combine the terms in the denominator: \( \frac{3(a-2) - 6(a+2)}{(a+2)(a-2)} \). Simplifying the numerator gives \( 3a - 6 - 6a - 12 = -3a - 18 \). The denominator becomes \( \frac{-3(a+6)}{(a+2)(a-2)} \).
05

Simplify the Numerator of the Main Fraction

In the numerator, which is \( \frac{5}{a+2} - \frac{1}{a-2} \), find a common denominator, \((a+2)(a-2)\). Rewrite the fractions as \( \frac{5(a-2)}{(a+2)(a-2)} \) and \( \frac{-1(a+2)}{(a+2)(a-2)} \).
06

Combine and Simplify the Numerator

The numerator becomes \( \frac{5(a-2) - (a+2)}{(a+2)(a-2)} \). Simplifying the expression inside the numerator gives \( 5a - 10 - a - 2 = 4a - 12 \). Thus, it is \( \frac{4(a-3)}{(a+2)(a-2)} \).
07

Form the Simplified Overall Fraction

Combine the simplified numerator and denominator: \( \frac{\frac{4(a-3)}{(a+2)(a-2)}}{\frac{-3(a+6)}{(a+2)(a-2)}} \). This simplifies to \( \frac{4(a-3)}{-3(a+6)} \).
08

Final Simplification

The simplified expression becomes \( -\frac{4(a-3)}{3(a+6)} \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Common Denominator
When simplifying complex fractions, finding a common denominator is an essential step. A complex fraction contains one or more fractions in its numerator, denominator, or both. To simplify these, we first need to make the denominators the same.

For example, consider the denominators in the expression \( \frac{5}{a+2} - \frac{1}{a-2} \). To combine these fractions, we must identify a common denominator, which is the product of the individual denominators:
  • \((a+2)\) and \((a-2)\) multiply to become \((a+2)(a-2)\).
  • Once a common denominator is found, each fraction is rewritten with this shared denominator.
This technique allows us to combine fractions by unifying their denominators, transforming them into a single cohesive fraction.

Without a common denominator, fractions cannot be combined effectively when they are added or subtracted. This concept is crucial when dealing with algebraic expressions, as it is the first step in simplifying the fractions present in a complex fraction.
Fraction Operations
Fraction operations involve addition, subtraction, multiplication, and division of fractions. When simplifying complex fractions:
  • Start by simplifying the fractions in both the numerator and denominator.
  • In our example, the numerator \( \frac{5}{a+2} - \frac{1}{a-2} \) is simplified by finding a common denominator and combining.
  • Similarly, simplify the denominator \( \frac{3}{2+a} + \frac{6}{2-a} \) by adjusting signs and denominators.
To add or subtract fractions, their denominators must be the same, as discussed in the common denominator section. Multiplying fractions is straightforward: multiply the numerators together and the denominators together. For division, multiply by the reciprocal of the second fraction.

These operations when applied step-by-step make complex fractions manageably simple, breaking down the overall expression into smaller, more accessible parts.
Algebraic Simplification
Algebraic simplification is about reducing expressions to their simplest form to make them easier to understand and work with. Once you have found a common denominator and executed fraction operations, it's time to simplify the result.
  • Simplify expressions by combining like terms. For example, in the numerator \( 5a - 10 - a - 2 \) becomes \( 4a - 12 \).
  • Factor common elements to make the expression neater. For instance, \( 4a - 12 \) factors to \( 4(a-3) \).
Next, simplify the whole fraction. Combine your simplified numerator and denominator, cancelling out any like terms if possible. For example, converting \( \frac{\frac{4(a-3)}{(a+2)(a-2)}}{\frac{-3(a+6)}{(a+2)(a-2)}} \) to \( \frac{4(a-3)}{-3(a+6)} \).

Using algebraic simplification, complex problems become much simpler, ensuring that the final result is not only correct but also easy to interpret.

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Most popular questions from this chapter

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