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Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
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Capitolo 3, Problema 100

Solve by completing the square: 2x² – 5x + 1 = 0.

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1
Start by dividing the entire equation by the coefficient of \(x^2\), which is 2, to make the coefficient of \(x^2\) equal to 1. This gives: \(x^2 - \frac{5}{2}x + \frac{1}{2} = 0\).
Next, move the constant term to the right side of the equation: \(x^2 - \frac{5}{2}x = -\frac{1}{2}\).
To complete the square, take half of the coefficient of \(x\), which is \(-\frac{5}{2}\), divide it by 2 to get \(-\frac{5}{4}\), then square it to get \(\left(-\frac{5}{4}\right)^2 = \frac{25}{16}\). Add this value to both sides of the equation.
Rewrite the left side as a perfect square trinomial: \(\left(x - \frac{5}{4}\right)^2 = -\frac{1}{2} + \frac{25}{16}\).
Simplify the right side by finding a common denominator and combining the terms, then solve for \(x\) by taking the square root of both sides and isolating \(x\).

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