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Ch. 3 - Polynomial and Rational Functions
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
4장, 문제 91

Solve each inequality in Exercises 86–91 using a graphing utility. 1/(x + 1) ≤ 2/(x + 4)

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Start by rewriting the inequality to have all terms on one side: \(\frac{1}{x + 1} - \frac{2}{x + 4} \leq 0\).
Find a common denominator to combine the fractions: the common denominator is \((x + 1)(x + 4)\), so rewrite the expression as \(\frac{(x + 4) - 2(x + 1)}{(x + 1)(x + 4)} \leq 0\).
Simplify the numerator: expand and combine like terms to get \(\frac{x + 4 - 2x - 2}{(x + 1)(x + 4)} \leq 0\), which simplifies to \(\frac{-x + 2}{(x + 1)(x + 4)} \leq 0\).
Identify the critical points by setting the numerator and denominator equal to zero: numerator zero at \(x = 2\), denominator zero at \(x = -1\) and \(x = -4\). These points divide the number line into intervals to test.
Use a graphing utility to plot the function \(f(x) = \frac{-x + 2}{(x + 1)(x + 4)}\) and determine where \(f(x) \leq 0\) by observing the graph and considering the domain restrictions where the denominator is not zero.

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주요 개념

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

Rational Inequalities

Rational inequalities involve expressions with variables in the denominator. Solving them requires finding values of the variable that make the inequality true, while considering restrictions where the denominator is zero to avoid undefined expressions.
추천 영상:
3:21
Nonlinear Inequalities

Domain Restrictions

Domain restrictions are values that make the denominator zero, causing the expression to be undefined. Identifying these values is crucial before solving inequalities, as they split the number line into intervals for testing solutions.
추천 영상:
3:51
Domain Restrictions of Composed Functions

Graphing Utility for Inequalities

A graphing utility helps visualize the functions involved in the inequality by plotting their graphs. It allows for identifying where one function is less than or equal to another, making it easier to determine solution intervals accurately.
추천 영상:
7:02
Linear Inequalities