Chapter 1: Problem 82
Factor the expression completely. $$49-4 y^{2}$$
Short Answer
Expert verified
The expression \(49 - 4y^2\) factors to \((7 - 2y)(7 + 2y)\).
Step by step solution
01
Recognize the Form
The expression \(49 - 4y^2\) is in the form of \(a^2 - b^2\), which is known as a difference of squares. This type of expression can be factored using the identity: \(a^2 - b^2 = (a - b)(a + b)\).
02
Identify \(a^2\) and \(b^2\)
In the expression \(49 - 4y^2\), identify \(a^2 = 49\) and \(b^2 = 4y^2\). Recognize that \(49\) is a perfect square, so \(a = 7\). For \(4y^2\), we also have a perfect square, so \(b = 2y\).
03
Apply the Difference of Squares Formula
Using the values of \(a\) and \(b\) found in Step 2, apply the difference of squares formula: \((a - b)(a + b)\). Substitute \(a = 7\) and \(b = 2y\) into the formula: \((7 - 2y)(7 + 2y)\).
04
Verify the Factorization
Expand the factored expression \((7 - 2y)(7 + 2y)\) to verify correctness: \(7 \times 7 + 7 \times 2y - 2y \times 7 - 2y \times 2y\). This simplifies to \(49 - 4y^2\), confirming the factorization is correct.
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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 formula used in algebra to simplify expressions. It relies on the identity that states:
- Given any two terms, where both terms are perfect squares, their difference can be factorized using the formula: \[a^2 - b^2 = (a - b)(a + b)\]
- This formula is incredibly useful because it reduces a binomial into a product of two binomials.
Perfect Squares
A perfect square is an expression that is obtained by multiplying a number or an algebraic term by itself. In the world of polynomials and algebra, understanding perfect squares is crucial.
- For example, \(a^2\) is a perfect square because it is the result of multiplying \(a\) by itself.
- Similarly, \(b^2\) is a perfect square, derived from \(b \times b\).
Polynomial Factoring
Polynomial factoring is the process of expressing a polynomial as the product of its factors. It's a fundamental tool in algebra that simplifies expressions and solves equations.
- One of the most common methods is to recognize patterns such as the difference of squares or perfect squares within an expression.
- These patterns allow for immediate simplification through well-established identities.