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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 101

Solve each equation. x-2/3+x-1/3-6=0

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1
Recognize that the equation involves negative fractional exponents: \(x^{-\frac{2}{3}} + x^{-\frac{1}{3}} - 6 = 0\). To simplify, introduce a substitution to rewrite the equation in terms of a single variable. Let \(y = x^{-\frac{1}{3}}\).
Rewrite each term in the equation using the substitution \(y = x^{-\frac{1}{3}}\). Note that \(x^{-\frac{2}{3}} = (x^{-\frac{1}{3}})^2 = y^2\). So the equation becomes \(y^2 + y - 6 = 0\).
Solve the quadratic equation \(y^2 + y - 6 = 0\) by factoring, completing the square, or using the quadratic formula. This will give you the possible values for \(y\).
After finding the values of \(y\), recall that \(y = x^{-\frac{1}{3}} = \frac{1}{x^{\frac{1}{3}}}\). Rewrite this as \(x^{\frac{1}{3}} = \frac{1}{y}\) to solve for \(x\).
Finally, solve for \(x\) by cubing both sides: \(x = \left( \frac{1}{y} \right)^3\). Calculate this for each value of \(y\) found in step 3 to get the solutions for \(x\).

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주요 개념

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

Rational Exponents

Rational exponents represent roots and powers combined, where an exponent like x^(m/n) means the nth root of x raised to the mth power. Understanding how to manipulate expressions with rational exponents is essential for rewriting and simplifying the given equation.
추천 영상:
04:06
Rational Exponents

Substitution Method

The substitution method involves replacing a complex expression with a single variable to simplify solving equations. For example, letting y = x^(-1/3) transforms the equation into a quadratic form, making it easier to solve.
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Choosing a Method to Solve Quadratics

Solving Quadratic Equations

Quadratic equations are polynomial equations of degree two, typically solved by factoring, completing the square, or using the quadratic formula. After substitution, the equation becomes quadratic, so knowing how to solve it is crucial.
추천 영상:
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Solving Quadratic Equations by Factoring