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Ch. 1 - Equations and Inequalities
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 59

Solve each equation in Exercises 41–60 by making an appropriate substitution. (y8y)2+5(y8y)14=0\(\left\)( y - \(\frac{8}{y}\) \(\right\))^2 + 5 \(\left\)( y - \(\frac{8}{y}\) \(\right\)) - 14 = 0

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1
Identify the substitution by letting \( t = y - \frac{8}{y} \). This simplifies the given equation into a quadratic in terms of \( t \).
Rewrite the original equation using the substitution: \( t^2 + 5t - 14 = 0 \).
Solve the quadratic equation \( t^2 + 5t - 14 = 0 \) using the quadratic formula \( t = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \), where \( a=1 \), \( b=5 \), and \( c=-14 \).
After finding the values of \( t \), substitute back \( t = y - \frac{8}{y} \) to form equations in terms of \( y \): \( y - \frac{8}{y} = t \).
Multiply both sides of each equation by \( y \) to clear the denominator, resulting in quadratic equations in \( y \). Solve these quadratics to find the values of \( y \).

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주요 개념

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

Substitution Method

The substitution method involves replacing a complex expression with a single variable to simplify the equation. In this problem, the expression (y - 8/y) can be substituted with a new variable, reducing the equation to a quadratic form that is easier to solve.
추천 영상:
04:03
Choosing a Method to Solve Quadratics

Quadratic Equations

A quadratic equation is a polynomial equation of degree two, typically in the form ax² + bx + c = 0. After substitution, the given equation becomes quadratic, allowing the use of factoring, completing the square, or the quadratic formula to find solutions.
추천 영상:
05:35
Introduction to Quadratic Equations

Solving Rational Expressions

The original expression involves a rational term (8/y), so after finding solutions for the substituted variable, it is important to back-substitute and solve for y. This may involve solving rational equations and checking for extraneous solutions where the denominator is zero.
추천 영상:
가이드 코스
02:58
Rationalizing Denominators