$\begin{array} {l} x = \dfrac { 2 \sqrt{ 15 } } { 5 } \\ x = - \dfrac { 2 \sqrt{ 15 } } { 5 } \end{array}$
$x = \dfrac { \color{#FF6800}{ - } \color{#FF6800}{ 0 } \pm \sqrt{ 0 ^ { 2 } - 4 \times 5 \times \left ( - 12 \right ) } } { 2 \times 5 }$
$ $ 0 has no sign $ $
$x = \dfrac { \color{#FF6800}{ 0 } \pm \sqrt{ 0 ^ { 2 } - 4 \times 5 \times \left ( - 12 \right ) } } { 2 \times 5 }$
$x = \dfrac { 0 \pm \sqrt{ \color{#FF6800}{ 0 } ^ { \color{#FF6800}{ 2 } } - 4 \times 5 \times \left ( - 12 \right ) } } { 2 \times 5 }$
$ $ The power of 0 is 0 $ $
$x = \dfrac { 0 \pm \sqrt{ \color{#FF6800}{ 0 } - 4 \times 5 \times \left ( - 12 \right ) } } { 2 \times 5 }$
$\color{#FF6800}{ x } = \color{#FF6800}{ \dfrac { 0 \pm \sqrt{ 0 - 4 \times 5 \times \left ( - 12 \right ) } } { 2 \times 5 } }$
$ $ Organize the expression $ $
$\color{#FF6800}{ x } = \color{#FF6800}{ \dfrac { 0 \pm \sqrt{ 240 } } { 2 \times 5 } }$
$x = \dfrac { 0 \pm \sqrt{ \color{#FF6800}{ 240 } } } { 2 \times 5 }$
$ $ Organize the part that can be taken out of the radical sign inside the square root symbol $ $
$x = \dfrac { 0 \pm \color{#FF6800}{ 4 } \sqrt{ \color{#FF6800}{ 15 } } } { 2 \times 5 }$
$x = \dfrac { 0 \pm 4 \sqrt{ 15 } } { \color{#FF6800}{ 2 } \color{#FF6800}{ \times } \color{#FF6800}{ 5 } }$
$ $ Multiply $ 2 $ and $ 5$
$x = \dfrac { 0 \pm 4 \sqrt{ 15 } } { \color{#FF6800}{ 10 } }$
$\color{#FF6800}{ x } = \color{#FF6800}{ \dfrac { 0 \pm 4 \sqrt{ 15 } } { 10 } }$
$ $ Separate the answer $ $
$\begin{array} {l} \color{#FF6800}{ x } = \color{#FF6800}{ \dfrac { 0 + 4 \sqrt{ 15 } } { 10 } } \\ \color{#FF6800}{ x } = \color{#FF6800}{ \dfrac { 0 - 4 \sqrt{ 15 } } { 10 } } \end{array}$
$\begin{array} {l} x = \dfrac { \color{#FF6800}{ 0 } + 4 \sqrt{ 15 } } { 10 } \\ x = \dfrac { 0 - 4 \sqrt{ 15 } } { 10 } \end{array}$
$ $ 0 does not change when you add or subtract $ $
$\begin{array} {l} x = \dfrac { 4 \sqrt{ 15 } } { 10 } \\ x = \dfrac { 0 - 4 \sqrt{ 15 } } { 10 } \end{array}$
$\begin{array} {l} x = \color{#FF6800}{ \dfrac { 4 \sqrt{ 15 } } { 10 } } \\ x = \dfrac { 0 - 4 \sqrt{ 15 } } { 10 } \end{array}$
$ $ Do the reduction of the fraction format $ $
$\begin{array} {l} x = \color{#FF6800}{ \dfrac { 2 \sqrt{ 15 } } { 5 } } \\ x = \dfrac { 0 - 4 \sqrt{ 15 } } { 10 } \end{array}$
$\begin{array} {l} x = \dfrac { 2 \sqrt{ 15 } } { 5 } \\ x = \dfrac { \color{#FF6800}{ 0 } - 4 \sqrt{ 15 } } { 10 } \end{array}$
$ $ 0 does not change when you add or subtract $ $
$\begin{array} {l} x = \dfrac { 2 \sqrt{ 15 } } { 5 } \\ x = \dfrac { - 4 \sqrt{ 15 } } { 10 } \end{array}$
$\begin{array} {l} x = \dfrac { 2 \sqrt{ 15 } } { 5 } \\ x = \color{#FF6800}{ \dfrac { - 4 \sqrt{ 15 } } { 10 } } \end{array}$
$ $ Do the reduction of the fraction format $ $
$\begin{array} {l} x = \dfrac { 2 \sqrt{ 15 } } { 5 } \\ x = \color{#FF6800}{ \dfrac { - 2 \sqrt{ 15 } } { 5 } } \end{array}$
$\begin{array} {l} x = \dfrac { 2 \sqrt{ 15 } } { 5 } \\ x = \color{#FF6800}{ \dfrac { - 2 \sqrt{ 15 } } { 5 } } \end{array}$
$ $ Move the minus sign to the front of the fraction $ $
$\begin{array} {l} x = \dfrac { 2 \sqrt{ 15 } } { 5 } \\ x = \color{#FF6800}{ - } \color{#FF6800}{ \dfrac { 2 \sqrt{ 15 } } { 5 } } \end{array}$