Solve each equation using completing the square. -2x2 + 4x + 3 = 0
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First, rewrite the equation to isolate the quadratic term with a positive coefficient. Start with the equation \(-2x^2 + 4x + 3 = 0\). Divide every term by \(-2\) to get \(x^2 - 2x - \frac{3}{2} = 0\).
Next, move the constant term to the other side of the equation: \(x^2 - 2x = \frac{3}{2}\).
To complete the square, take half of the coefficient of \(x\), which is \(-2\), divide it by 2 to get \(-1\), and then square it to get \$1$. Add this value to both sides: \(x^2 - 2x + 1 = \frac{3}{2} + 1\).
Rewrite the left side as a perfect square trinomial: \((x - 1)^2 = \frac{3}{2} + 1\). Simplify the right side by expressing \$1$ as \(\frac{2}{2}\) and adding the fractions.
Finally, take the square root of both sides to solve for \(x\): \(x - 1 = \pm \sqrt{\text{right side}}\). Then isolate \(x\) by adding \$1$ to both sides.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Completing the Square
Completing the square is a method used to solve quadratic equations by transforming the equation into a perfect square trinomial. This involves creating a binomial squared expression on one side, making it easier to solve for the variable by taking square roots.
Solving Quadratic Equations by Completing the Square
Quadratic Equation Standard Form
A quadratic equation is typically written in the form ax² + bx + c = 0. To complete the square, the equation must be manipulated into this form, often requiring dividing through by the coefficient of x² if it is not 1.
After completing the square, the equation is rewritten so that the variable term is isolated on one side. This allows taking the square root of both sides, leading to two possible solutions due to the ± sign.