# Solving Quadratic Equations

### Solving Quadratic Equations

To solve a quadratic equation means to find all the roots of the quadratic equations.
Example:
Find the roots of the quadratic equations
a. $${x^2} = 9$$
b. $${2x^2} - 98 = 0$$
Answer:
a.
$\begin{array}{l} {x^2} = 9\\ x = \pm \sqrt 9 \\ x = \pm 3 \end{array}$ b.
$\begin{array}{l} 2{x^2} - 98 = 0\\ 2{x^2} = 98\\ {x^2} = \frac{{98}}{2} = 49\\ x = \pm \sqrt {49} = \pm 7 \end{array}$

A quadratic equation may be solve by using one of the following method
1. Factorisation
2. Completing the square
3. Using quadratic formula