Investigation: Derive the Quadratic Formula (HSC SSCE Mathematics Advanced): Quizzes

$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$

Completing the square

$x = 2$ or $x = -4$

$\frac{b^2}{4a^2}$

The discriminant

$(x + 1)^2 = 9$

$x^2 + \frac{b}{a}x = -\frac{c}{a}$

There are two solutions

$b$ and $c$

$\left(x + \frac{b}{2a}\right)^2 = \frac{b^2 - 4ac}{4a^2}$