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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 95

Solve each equation. 4(x+1)4-13(x+1)2=-9

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Start by making a substitution to simplify the equation. Let \(y = (x+1)^2\). This transforms the original equation \(4(x+1)^4 - 13(x+1)^2 = -9\) into \(4y^2 - 13y = -9\).
Rewrite the equation in standard quadratic form by moving all terms to one side: \(4y^2 - 13y + 9 = 0\).
Solve the quadratic equation \(4y^2 - 13y + 9 = 0\) using the quadratic formula: \(y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \(a=4\), \(b=-13\), and \(c=9\).
After finding the values of \(y\), recall that \(y = (x+1)^2\). For each solution \(y_i\), solve the equation \((x+1)^2 = y_i\) by taking the square root of both sides: \(x+1 = \pm \sqrt{y_i}\).
Finally, solve for \(x\) by isolating it: \(x = -1 \pm \sqrt{y_i}\). These values of \(x\) are the solutions to the original equation.

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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, letting y = (x + 1)^2 transforms the quartic equation into a quadratic form, making it easier to solve.
추천 영상:
04:03
Choosing a Method to Solve Quadratics

Solving Quadratic Equations

Once the equation is rewritten as a quadratic in terms of y, techniques such as factoring, completing the square, or using the quadratic formula can be applied to find the values of y. These solutions are then used to find x.
추천 영상:
06:08
Solving Quadratic Equations by Factoring

Back-Substitution and Solving for x

After finding the values of y, substitute back y = (x + 1)^2 to solve for x. This typically involves taking square roots and considering both positive and negative roots to find all possible solutions.
추천 영상:
5:48
Solving Systems of Equations - Substitution