设 A= (2n-1 31-2) ，B= (-112 -215) 求2A-3B．

设
A=
(2n-1
31-2)
，B=
(-112
-215)
求2A-3B．
【正确答案】：2A-3B=2 (2 0 -1 3 1 -2) -3 (-1 1 2 -9 1 5) = (4 0 -2 6 2 -4) - (-3 3 6 -6 3 15) = (7 -3 -8 12 -1 -19)