Completing the Square
Overview
Goal. Complete the square for x² + bx by adding (b/2)² — including fractional values when b is odd — solve quadratic equations this way, and rewrite a quadratic in vertex form.
Completing the square (definition). Adding the constant (b/2)² to x² + bx so the expression becomes the perfect square (x + b/2)².
Lesson Notes
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Lesson Video
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Interactive Activity
Goal. Turn x² + bx into a perfect square by adding (b/2)², solve equations by completing the square, and rewrite a quadratic in vertex form.
Completing the square (definition). Adding the constant (b/2)² to x² + bx so the expression becomes the perfect square (x + b/2)².