If A = \(\left[ {\begin{array}{*{20}{c}} 0&2\\ 3&{ - 4} \end{array}} \right]\) and kA = \(\left[ {\begin{array}{*{20}{c}} {\rm{0}}&{{\rm{3a}}}\\ {{\rm{2b}}}&{{\rm{24}}} \end{array}} \right]\), then the value of k, a, b are respectively