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Ch. 1 - Equations and Inequalities
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 89

Use the method described in Exercises 83–86, if applicable, and properties of absolute value to solve each equation or inequality. (Hint: Exercises 99 and 100 can be solved by inspection.) | 3x2 - 14x | = 5

검증된 단계별 안내
1
Recognize that the equation involves an absolute value: \(|3x^2 - 14x| = 5\). The definition of absolute value tells us that \(|A| = B\) means \(A = B\) or \(A = -B\) when \(B \geq 0\).
Set up two separate equations based on the absolute value property: \(3x^2 - 14x = 5\) and \(3x^2 - 14x = -5\).
Solve each quadratic equation separately. For the first equation \(3x^2 - 14x - 5 = 0\), use the quadratic formula: \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \(a=3\), \(b=-14\), and \(c=-5\).
Similarly, solve the second quadratic equation \(3x^2 - 14x + 5 = 0\) using the quadratic formula with \(a=3\), \(b=-14\), and \(c=5\).
After finding the solutions from both quadratics, check each solution by substituting back into the original absolute value equation to ensure they satisfy \(|3x^2 - 14x| = 5\).

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주요 개념

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

Absolute Value Equations

An absolute value equation involves expressions within absolute value bars, which represent the distance from zero on the number line. To solve |A| = B, where B ≥ 0, we set A = B and A = -B, creating two separate equations to solve. Understanding this principle is essential for breaking down the given equation.
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Categorizing Linear Equations

Quadratic Equations

Quadratic equations are polynomial equations of degree two, typically in the form ax² + bx + c = 0. Solving them involves factoring, completing the square, or using the quadratic formula. Since the expression inside the absolute value is quadratic, solving the resulting equations requires knowledge of these methods.
추천 영상:
05:35
Introduction to Quadratic Equations

Properties of Absolute Value Inequalities

Properties of absolute value inequalities help in solving equations or inequalities involving absolute values by considering cases based on the definition of absolute value. For example, |X| = k implies X = k or X = -k, and understanding these properties aids in correctly setting up and solving the problem.
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Linear Inequalities