Question

O valor do determinante A=

Answer 1

$A= \left[\begin{array}{ccc}1&2&3\\3&2&1\\0&4&3\end{array}\right] \\ \\ \\ detA= \left[\begin{array}{ccccc}1&2&3&1&2\\3&2&1&3&2\\0&4&3&0&4\end{array}\right] \\ \\ detA=Diagonal~~principal-diagonal~secund\acute{a}ria \\ \\ detA=6+0+36-(0+4+18) \\ \\ detA=6+36-4-18 \\ \\ detA=42-22 \\ \\ detA=20\mapsto letra~~A$