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Ch. R - Review of Basic Concepts
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
1장, 문제 153

Rationalize each denominator. Assume all variables represent nonnegative numbers and that no denominators are 0. (p - 4) / (√p + 2)

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1
Identify the expression to rationalize: \(\frac{p - 4}{\sqrt{p} + 2}\). The goal is to eliminate the square root from the denominator.
Multiply both the numerator and the denominator by the conjugate of the denominator. The conjugate of \(\sqrt{p} + 2\) is \(\sqrt{p} - 2\). So multiply by \(\frac{\sqrt{p} - 2}{\sqrt{p} - 2}\).
Apply the multiplication: The numerator becomes \((p - 4)(\sqrt{p} - 2)\) and the denominator becomes \((\sqrt{p} + 2)(\sqrt{p} - 2)\).
Use the difference of squares formula for the denominator: \((a + b)(a - b) = a^2 - b^2\). Here, \(a = \sqrt{p}\) and \(b = 2\), so the denominator simplifies to \(p - 4\).
Write the new expression as \(\frac{(p - 4)(\sqrt{p} - 2)}{p - 4}\). Since \(p - 4\) is common in numerator and denominator, consider simplifying the expression further if possible.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Rationalizing the Denominator

Rationalizing the denominator involves eliminating any square roots or irrational numbers from the denominator of a fraction. This is done to simplify the expression and make it easier to work with. Typically, this is achieved by multiplying the numerator and denominator by a conjugate or an appropriate radical.
추천 영상:
02:58
Rationalizing Denominators

Conjugates of Binomials

The conjugate of a binomial expression like (√p + 2) is (√p - 2). Multiplying a binomial by its conjugate results in a difference of squares, which removes the square root terms. This technique is essential for rationalizing denominators containing sums or differences involving radicals.
추천 영상:
05:33
Complex Conjugates

Properties of Square Roots and Nonnegative Variables

Since variables represent nonnegative numbers, the square root function √p is defined and nonnegative. This ensures that expressions involving √p behave predictably, allowing simplification without considering complex or negative values. Understanding this helps avoid extraneous solutions or undefined expressions.
추천 영상:
02:20
Imaginary Roots with the Square Root Property