(1)
|3A1+A2,A2+A3,2A2-A3|
=|3A1+A2,A2+A3+(2A2-A3),2A2-A3| (行列式的性质:C2+C3)
=|3A1+A2,3A2,2A2-A3|
=3|3A1+A2,A2,2A2-A3| (行列式的性质)
=3|3A1+A2-A2,A2,2A2-A3-2A2| (行列式的性质:C1-C2,C3-2C2)
=3|3A1,A2,-A3|
=3×3×(-1)×|A1,A2,A3|
=-9×(-5)
=45
(2)
|3A1+A3,A2+A3,3A1-A2|
=|3A1+A3-(3A1-A2),A2+A3,3A1-A2|(行列式的性质:C1-C3)
=|A3+A2,A2+A3,3A1-A2|
=0 (行列式性质:两列完全一样,行列式为0)