解答题
27.设
【正确答案】(1)D=
=1×A13=M13
(2)M31+M33+M34=1×A31+0×A32+1×A33+(-1)×A34
=1×A31=M31
=-3×A12=
=1×A13=M13(2)M31+M33+M34=1×A31+0×A32+1×A33+(-1)×A34
=1×A31=M31
=-3×A12=
【答案解析】