Quadratic Equations — Quick Revision
A quadratic equation has the form ax² + bx + c = 0 where a ≠ 0. Solve by factorisation, completing the square, or the quadratic formula. The discriminant decides the nature of the roots.
Key Points
- •Standard form: ax² + bx + c = 0
- •Discriminant D = b² − 4ac
- •D>0 ⇒ two real roots
- •D=0 ⇒ equal roots
- •D<0 ⇒ no real roots