Answer
0
Work Step by Step
$$\eqalign{
& \left| {\matrix{
2 & 3 & 0 \cr
1 & 9 & 0 \cr
{ - 1} & { - 2} & 0 \cr
} } \right| \cr
& {\rm{Calculating\, the\, determinant\, by \,expanding\, the\, third \,column}} \cr
& \left| {\matrix{
2 & 3 & 0 \cr
1 & 9 & 0 \cr
{ - 1} & { - 2} & 0 \cr
} } \right| = 0\left| {\matrix{
1 & 9 \cr
{ - 1} & { - 2} \cr
} } \right| - 0\left| {\matrix{
2 & 3 \cr
{ - 1} & { - 2} \cr
} } \right| + 0\left| {\matrix{
2 & 3 \cr
1 & 9 \cr
} } \right| \cr
& {\rm{Solving}} \cr
& \left| {\matrix{
2 & 3 & 0 \cr
1 & 9 & 0 \cr
{ - 1} & { - 2} & 0 \cr
} } \right| = 0 \cr} $$
