2.3 Solving Quadratic Equations - SPM Additional Mathematics

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