Find the value of k so that the lines  \(\frac{{1 - x}}{3} = \frac{{7y - 14}}{{2k}} = \frac{{z - 3}}{2}\;and\frac{{7 - 7x}}{{3k}} = \frac{{5 - y}}{1} = \frac{{6 - z}}{5}\) are perpendicular to each other?