Alright, start with simplifying both sides
\(\frac{2}{7} k+ \frac{-3}{8} = \frac{-19}{8}\)
Than add \(\frac{3}{8}\) to both sides.
\(\frac{2}{7}k + \frac{-3}{8} + \frac{3}{8} =\frac{-19}{8} + \frac{3}{8}\)
which is \(\frac{2}{7} k=-2\)
After this, multiply each side by \(\frac{7}{2}\)
\(( \frac{7}{2})* \frac{2}{7} k= ( \frac{7}{2})*(-2)\)
So, your final answer is K=-7