If $A + \left[ {\begin{array}{cccccccccccccccccccc}{\cfrac{2}{3}}&1&{\cfrac{5}{3}}\\{\cfrac{1}{3}}&{\cfrac{2}{3}}&{\cfrac{4}{3}}\\{\cfrac{7}{3}}&2&{\cfrac{2}{3}}\end{array}} \right]$and $B = \left[ {\begin{array}{cccccccccccccccccccc}{\cfrac{2}{5}}&{\cfrac{3}{5}}&1\\{\cfrac{1}{5}}&{\cfrac{2}{5}}&{\cfrac{4}{5}}\\{\cfrac{7}{5}}&{\cfrac{6}{5}}&{\cfrac{2}{5}}\end{array}} \right],$ then compute $3A - 5B.$

.:

$3A - 5B = 3\left[ {\begin{array}{cccccccccccccccccccc}{\cfrac{2}{3}}&1&{\cfrac{5}{3}}\\{\cfrac{1}{3}}&{\cfrac{2}{3}}&{\cfrac{4}{3}}\\{\cfrac{7}{3}}&2&{\cfrac{2}{3}}\end{array}} \right] - 5\left[ {\begin{array}{cccccccccccccccccccc}{\cfrac{2}{5}}&{\cfrac{3}{5}}&1\\{\cfrac{1}{5}}&{\cfrac{2}{5}}&{\cfrac{4}{5}}\\{\cfrac{7}{5}}&{\cfrac{6}{5}}&{\cfrac{2}{5}}\end{array}} \right]$

$= \left[ {\begin{array}{cccccccccccccccccccc}2&3&5\\1&2&4\\7&6&2\end{array}} \right] - \left[ {\begin{array}{cccccccccccccccccccc}2&3&5\\1&2&4\\7&6&2\end{array}} \right] = \left[ {\begin{array}{cccccccccccccccccccc}0&0&0\\0&0&0\\0&0&0\end{array}} \right]$