[tex]\begin{cases}\large\bf{\green{ \implies}} \tt \: - \frac{6}{5} \: k \: = \: 12 \\ \\ \large\bf{\green{ \implies}} \tt \: - \frac{6k}{5} \: = \: 12 \\ \\ \large\bf{\green{ \implies}} \tt \: - 6k \: = \: 12 \: \times \: 5 \\ \\ \large\bf{\green{ \implies}} \tt \: - 6k \: = \: 60 \\ \\ \large\bf{\green{ \implies}} \tt \: k \: = \: \cancel\frac{60}{ - 6} \\ \\ \large\bf{\green{ \implies}} \tt \: k \: = \: - 10 \end{cases}[/tex]
