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Complex Solutions of Quadratics

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A quadratic with a negative discriminant has two complex solutions, and they are complex conjugates of each other.

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x² + 4 = 0 gives x = ±√(−4) = ±2i, and the check closes: (2i)² + 4 = −4 + 4 = 0.

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Complex solutions arrive in conjugate pairs, never alone.

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