Introduction
A quadratic equation is a second-degree polynomial equation in a single variable, written in the standard form:
ax² + bx + c = 0, where a ≠ 0.
Methods of Solving
- Factorization — quick when roots are integers.
- Completing the Square — useful for deriving the quadratic formula.
- Quadratic Formula — works for all equations: x = (-b ± √(b² - 4ac)) / 2a
Discriminant
D = b² - 4ac
- D > 0 → two distinct real roots
- D = 0 → two equal real roots
- D < 0 → no real roots