College Algebra / Unit 4 Alg 222 short lesson, about 20 seconds
Equations Quadratic in Form
Captions available
The idea
An equation is quadratic in form when a substitution for a repeated expression turns it into a quadratic.
In practice
x⁴ − 5x² + 4 = 0 under u = x² becomes u² − 5u + 4 = 0: u is 1 or 4, so x is ±1 and ±2.
Where people slip
Translate back to x; u is scaffolding.
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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