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Ch. 1 - Equations and Inequalities
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 2, Problem 87

Solve each equation. 2x4-7x2+5=0

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1
Recognize that the equation \$2x^{4} - 7x^{2} + 5 = 0\( is a quartic equation but can be treated as a quadratic in terms of \)x^{2}\(. To do this, let \)u = x^{2}$.
Rewrite the equation in terms of \(u\): \$2u^{2} - 7u + 5 = 0$.
Solve the quadratic equation \$2u^{2} - 7u + 5 = 0\( using the quadratic formula: \(u = \frac{-b \pm \sqrt{b^{2} - 4ac}}{2a}\), where \)a=2\(, \)b=-7\(, and \)c=5$.
After finding the values of \(u\), substitute back \(u = x^{2}\) to get equations of the form \(x^{2} = u\).
Solve each equation \(x^{2} = u\) by taking the square root of both sides, remembering to consider both the positive and negative roots: \(x = \pm \sqrt{u}\).

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