Skip to main content
Ch. 1 - Equations and Inequalities
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 94

Solve each equation. (x+5)2/3+(x+5)1/3-20=0

검증된 단계별 안내
1
Start by making a substitution to simplify the equation. Let \(y = (x+5)^{1/3}\), which means \(y^2 = (x+5)^{2/3}\).
Rewrite the original equation \((x+5)^{2/3} + (x+5)^{1/3} - 20 = 0\) in terms of \(y\) as \(y^2 + y - 20 = 0\).
Recognize that the equation \(y^2 + y - 20 = 0\) is a quadratic equation in standard form. Use the quadratic formula \(y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\) where \(a=1\), \(b=1\), and \(c=-20\) to find the values of \(y\).
After finding the values of \(y\), substitute back \(y = (x+5)^{1/3}\) to get equations of the form \((x+5)^{1/3} = y\) for each solution.
Solve each equation \((x+5)^{1/3} = y\) by cubing both sides to isolate \(x\): \(x + 5 = y^3\), then solve for \(x\) by subtracting 5.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
6m
도움이 되었나요?

주요 개념

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

Rational Exponents

Rational exponents represent roots and powers simultaneously, where the numerator is the power and the denominator is the root. For example, x^(2/3) means the cube root of x squared. Understanding how to manipulate and simplify expressions with rational exponents is essential for solving equations like the given one.
추천 영상:
04:06
Rational Exponents

Substitution Method

The substitution method involves replacing a complex expression with a single variable to simplify the equation. In this problem, letting y = (x+5)^(1/3) transforms the equation into a quadratic form, making it easier to solve. After solving for y, substitute back to find x.
추천 영상:
04:03
Choosing a Method to Solve Quadratics

Solving Quadratic Equations

Quadratic equations are polynomial equations of degree two and can be solved by factoring, completing the square, or using the quadratic formula. Once the substitution reduces the original equation to a quadratic in terms of y, these methods help find the values of y, which then lead to the solutions for x.
추천 영상:
06:08
Solving Quadratic Equations by Factoring