• \( \left| \begin{matrix} a_1 & a_2 \\ a_3 & a_4 \end{matrix} \right| \)

    \( \frac{\sqrt[a]{b+c}}{b+c} \)

    \(a+b\)

    When \(a \ne 0\), there are two solutions to \(ax^2 + bx + c = 0\) and they are
    \(x = {-b \pm \sqrt{b^2-4ac} \over 2a}.\)

    \( x = {-b \pm \sqrt{b^2-4ac} \over 2a}. \)