College Algebra / Unit 4 Alg 213 short lesson, about 20 seconds
Complex Solutions of Quadratics
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The idea
A quadratic with a negative discriminant has two complex solutions, and they are complex conjugates of each other.
In practice
x² + 4 = 0 gives x = ±√(−4) = ±2i, and the check closes: (2i)² + 4 = −4 + 4 = 0.
Where people slip
Complex solutions arrive in conjugate pairs, never alone.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
- Nothing. This is a starting point.
Unlocks
- Nothing yet depends on this.
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