The quadratic formula is used to find the roots (solutions) of a quadratic equation of the form:
$ ax^2+bx+c=0$
**Standard formula:** The general solution for the quadratic equation is given by
$ x=\frac{-b \pm \sqrt{b^2-4ac}}{2a} $
where $b^2-4ac$ is the discriminant:
- If $b^2 -4ac >0$, there are two distinct solutions.
- If $b^2 -4ac =0$, there is one unique solution.
- If $b^2 -4ac <0$, the roots are complex (no real solution).
**Simplified formula:** In the special case where $a=0$ the quadratic equation has the form:
$ x^2 +px -q =0$
This simplifies the solving formula to:
$ x=-\frac{p}{2} \pm \sqrt{\frac{p^2}{4}-q} $