Chapter 7: Problem 36
Perform the operations. Simplify, if possible. $$ \frac{t+5}{t-5}-\frac{t-5}{t+5} $$
Short Answer
Expert verified
The simplified expression is \(\frac{20t}{(t-5)(t+5)}\).
Step by step solution
01
Identify the common denominator
To subtract these two fractions, we need a common denominator. The denominators are \(t-5\) and \(t+5\). The common denominator is the product of these denominators, \((t-5)(t+5)\).
02
Rewrite each fraction with the common denominator
Multiply both the numerator and denominator of the first fraction by \(t+5\), and the second fraction by \(t-5\):\[\frac{t+5}{t-5} \cdot \frac{t+5}{t+5} = \frac{(t+5)^2}{(t-5)(t+5)}\]\[\frac{t-5}{t+5} \cdot \frac{t-5}{t-5} = \frac{(t-5)^2}{(t+5)(t-5)}\]
03
Subtract the numerators
Both fractions now have the same denominator, so we can subtract the numerators directly:\[\frac{(t+5)^2 - (t-5)^2}{(t-5)(t+5)}\]
04
Expand the squared terms
Expand \((t+5)^2\) and \((t-5)^2\) using the formula \((a+b)^2 = a^2 + 2ab + b^2\):\[(t+5)^2 = t^2 + 10t + 25\]\[(t-5)^2 = t^2 - 10t + 25\]
05
Simplify the numerator
Subtract the expanded forms of \((t+5)^2\) and \((t-5)^2\):\[(t^2 + 10t + 25) - (t^2 - 10t + 25) = t^2 + 10t + 25 - t^2 + 10t - 25 = 20t\]
06
Write the final simplified expression
Place the simplified numerator over the common denominator:\[\frac{20t}{(t-5)(t+5)}\]This is the simplified form of the original expression.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Common Denominator
When dealing with algebraic fractions, finding a common denominator is one of the first steps before adding or subtracting them. The common denominator helps to bring two or more fractions to a common base so they can be easily combined. In our example, we have the fractions \(\frac{t+5}{t-5}\) and \(\frac{t-5}{t+5}\). Each has different denominators: \(t-5\) and \(t+5\). To find a common denominator, you multiply the denominators together. This gives us
- \((t-5)(t+5)\)
Simplifying Expressions
Simplifying expressions is a crucial part of solving algebraic fractions effectively. After identifying the common denominator for our fractions, the next step is rewriting both fractions with the new denominator. We multiplied the \(\frac{t+5}{t-5}\) fraction by \(\frac{t+5}{t+5}\) and the \(\frac{t-5}{t+5}\) fraction by \(\frac{t-5}{t-5}\).This gives us:
- \(\frac{(t+5)^2}{(t-5)(t+5)}\) for the first fraction
- \(\frac{(t-5)^2}{(t+5)(t-5)}\) for the second fraction
- \((t+5)^2 = t^2 + 10t + 25\)
- \((t-5)^2 = t^2 - 10t + 25\)
Subtracting Fractions
Once both fractions have a common denominator, the subtraction process becomes straightforward. With the known expressions:
- \((t+5)^2 = t^2 + 10t + 25\)
- \((t-5)^2 = t^2 - 10t + 25\)