Bentuk \(x^2 − a^2 = 0\)

\begin{equation*} \begin{split} & x^2 - a^2 = 0 \\\\ & (x + a) \:.\: (x - a) = 0 \\\\ & x + a = 0 \text{ atau } x - a = 0 \\\\ & x = -a \text{ atau } x = a \end{split} \end{equation*}

Contoh

\begin{equation*} \begin{split} & x^2 - 9 = 0 \\\\ & x^2 - 3^2 = 0 \\\\ & (x + 3)(x - 3) = 0 \\\\ & x + 3 = 0 \text{ atau } x - 3 = 0 \\\\ & x = -3 \text{ atau } x = 3 \end{split} \end{equation*}

Bentuk \(ax^2 + bx + c = 0\)

Lakukan cara trial and error (lihat contoh soal)

Contoh

\begin{equation*} \begin{split} & x^2 + 3x + 2 = 0 \\\\ & (x + 2)(x + 1) = 0 \\\\ & x + 2 = 0 \text{ atau } x + 1 & = 0 \\\\ & x = -2 \text{ atau } x = -1 \end{split} \end{equation*}