### 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. $2{x}^{2}-98=0$

**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

- Factorisation
- Completing the square
- Using quadratic formula