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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 79a

For each equation, solve for x in terms of y. 4x2 - 2xy + 3y2 = 2

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1
Start with the given equation: \(4x^2 - 2xy + 3y^2 = 2\).
Rewrite the equation to isolate terms involving \(x\): \(4x^2 - 2xy = 2 - 3y^2\).
Recognize this as a quadratic equation in terms of \(x\): \(4x^2 - 2y x - (2 - 3y^2) = 0\).
Use the quadratic formula to solve for \(x\), where \(a = 4\), \(b = -2y\), and \(c = -(2 - 3y^2)\): \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\).
Substitute the values of \(a\), \(b\), and \(c\) into the quadratic formula and simplify under the square root to express \(x\) explicitly in terms of \(y\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Solving Quadratic Equations

A quadratic equation is a polynomial equation of degree two, typically in the form ax^2 + bx + c = 0. To solve for x, you can use methods such as factoring, completing the square, or the quadratic formula. In this problem, since the equation involves both x and y, treat y as a constant and solve the quadratic in terms of x.
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Treating Variables as Parameters

When solving for one variable in terms of another, consider the other variable as a constant or parameter. Here, y is treated as a known value, allowing the equation to be viewed as a quadratic in x. This approach helps isolate x and express it explicitly in terms of y.
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Using the Quadratic Formula

The quadratic formula x = [-b ± sqrt(b^2 - 4ac)] / (2a) provides solutions to any quadratic equation ax^2 + bx + c = 0. Identify coefficients a, b, and c with respect to x, substitute them into the formula, and simplify to express x in terms of y. This method is essential when factoring is difficult or impossible.
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