Consider the given singular matrix,
\(A = \left[ {\begin{array}{*{20}{c}} 8&{ - 6}&2\\ { - 6}&7&{ - 4}\\ 2&{ - 4}&3 \end{array}} \right]\)
If 15 is one of the eigen Value of the matrix A, then sum of the other two eigen values will be ______Enter numerical value using the virtual keypad. Round off where necessary.