If A = \( \left[ {\begin{array}{*{20}{c}} 1&0&0\\ 0&1&0\\ a&b&{ - 1} \end{array}} \right]\) and I is the unit matrix of order 3, then
A2 + 2A4 + 4A6 is equal to
1
7A8
2
7A7
3
8I
4
I
If A = \( \left[ {\begin{array}{*{20}{c}} 1&0&0\\ 0&1&0\\ a&b&{ - 1} \end{array}} \right]\) and I is the unit matrix of order 3, then
A2 + 2A4 + 4A6 is equal to