Chapter 0: Problem 50
Factor the expression completely. $$ 4 x^{2}-25 $$
Short Answer
Expert verified
The expression factors to \((2x - 5)(2x + 5)\).
Step by step solution
01
Recognize the Difference of Squares
The expression \( 4x^2 - 25 \) is a difference of squares. This can be identified because it follows the general pattern \( a^2 - b^2 \), where both terms are perfect squares.
02
Identify the Perfect Squares
Notice that \( 4x^2 \) is a perfect square, which is \((2x)^2\), and \( 25 \) is also a perfect square, which is \(5^2\).
03
Apply the Difference of Squares Formula
Use the formula for the difference of squares, \( a^2 - b^2 = (a - b)(a + b) \), where \( a = 2x \) and \( b = 5 \).
04
Write the Factored Form
Substitute \( a \) and \( b \) into the formula: \((2x - 5)(2x + 5)\).
05
Verify the Factorization
Expand \((2x - 5)(2x + 5)\) to check if it equals the original expression: \( (2x)(2x) + (2x)(5) - (5)(2x) - (5)(5) = 4x^2 - 25 \). This confirms 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
Polynomials sometimes take the form of a difference of squares, a concept that simplifies the factoring process considerably. In the case of the polynomial \(4x^2 - 25\), it is identified as a difference of squares. Here's why: the expression is structured as \(a^2 - b^2\), a recognizable theme in algebra where both terms are perfect squares. The hallmark of this structure enables a straightforward factorization using a specific formula.
- Notice 'difference' signifies subtraction between two terms.
- 'Squares' implies each term is the square of another number or expression.
Perfect Squares
Recognizing perfect squares within a polynomial expression paves the way to using the difference of squares method. For the polynomial \(4x^2 - 25\), identify each term as a perfect square. The term \(4x^2\) can be expressed as \((2x)^2\), and the term \(25\) can be rewritten as \(5^2\).
- Perfect squares are numbers or expressions that can be squared to yield another number.
- They simplify factorization by allowing simple substitution in factoring formulas.
Factored Form
The goal of factoring a polynomial is to express it in its factored form. This is a productive and powerful representation, often revealing roots and simplified structures. With the difference of squares, the polynomial \(4x^2 - 25\) factors to \((2x - 5)(2x + 5)\).
- The factored form breaks an expression into a product of simpler expressions.
- Recognizing this form can help solve equations and simplify expressions when required.