College Algebra / Unit 4 Alg 208 short lesson, about 20 seconds
The Quadratic Formula
Captions available
The idea
The quadratic formula solves every quadratic in standard form: x = (−b ± √(b² − 4ac)) / (2a).
In practice
For 2x² + 5x − 3 = 0: x = (−5 ± √49)/4 = (−5 ± 7)/4, landing on 1/2 and −3.
Where people slip
The formula is completing the square, run once for all time.
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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