Chapter 8: Problem 90
Factor expression. \((15-r)^{2}-s^{2}\)
Short Answer
Expert verified
The factored expression is \((15 - r - s)(15 - r + s)\).
Step by step solution
01
Recognize the Expression Form
Notice that the expression \((15-r)^{2} - s^{2}\) resembles the difference of squares. The difference of squares formula is \(a^2 - b^2 = (a - b)(a + b)\). Here, you have \(a = 15 - r\) and \(b = s\).
02
Apply the Difference of Squares Formula
Substitute \(a = 15 - r\) and \(b = s\) into the difference of squares formula: \((15-r)^{2} - s^{2} = ((15 - r) - s)((15 - r) + s)\).
03
Simplify the Expression
Simplify the expression further by performing the addition and subtraction in each factor. The factors become \((15 - r - s)\) and \((15 - r + s)\).
04
Write the Factored Form
Combine the simplified factors to express the fully factored form of the original expression. It results in: \((15 - r - s)(15 - r + s)\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Difference of Squares
The difference of squares is a special type of algebraic expression, structured as the subtraction of two square terms. This can be understood as a formula: \(a^2 - b^2 = (a - b)(a + b)\). It's essential because it provides a quick way to factor expressions of this kind. Here, \(a\) and \(b\) are placeholders for any expression that is being squared. In our given exercise, since \((15-r)^2 - s^2\) fits the structure of a difference of squares, we can identify \(a\) as \(15 - r\) and \(b\) as \(s\).
- Identify terms: Determine what is being squared—here, \((15-r)\) and \(s\).
- Use the identity: Apply \((a - b)(a + b)\) to factor the expression efficiently.
Algebraic Expressions
Algebraic expressions are combinations of variables, numbers, and operators (like addition or subtraction) that represent real-world quantities or scenarios. They form the basis of algebra and can be simple or complex, ranging from single-variable equations to multi-variable polynomials.In our exercise, the expression \((15-r)^2 - s^2\) involves both subtraction and exponentiation, making it a little more complex. Here are some key points to understand about algebraic expressions:
- Variables and Constants: In our case, \(r\) and \(s\) are variables that can take any value, while 15 is a constant number.
- Operations: This includes basic arithmetic and power operations (squared terms here).
- Structure: Knowing how the terms are arranged helps in identifying patterns like the difference of squares.
Step-by-Step Solution
Walking through the step-by-step solution of the given exercise ensures clarity and a deeper understanding of each stage in the factoring process.1. **Recognize the Pattern:** - Identify that the expression resembles a difference of squares, a common pattern that simplifies factoring. - Recall \((15-r)^2 - s^2\) is similar to \(a^2 - b^2\) with \(a = 15 - r\) and \(b = s\).2. **Apply the Formula:** - Plug \(a\) and \(b\) into the difference of squares formula: \((a - b)(a + b)\). - For our terms: \(((15 - r) - s)((15 - r) + s)\).3. **Simplify the Result:** - Perform the arithmetic operation within each factor to arrive at the correct result: \((15 - r - s)\) and \((15 - r + s)\).4. **Write the Factored Form:** - Combine these results to get the fully factored expression: \((15 - r - s)(15 - r + s)\).Each step builds on the previous one, ensuring that the final product is both accurate and easy to comprehend. These steps are universally applicable to a wide range of algebraic expressions that fit certain patterns, making the approach both practical and versatile.