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矩阵A=(-1,0,0;0,1,2;0,2,3)令A=-1 0 0 1 0 00 1 2 0 1 00 2 3 0 0 1→1 0 0 -1 0 00 1 2 0 1 00 0 -1 0 -2 1→1 0 0 -1 0 00 1 0 0 -3 20 0 1 0 2 -1所以A的逆为-1 0 00 -3 2 0 2 -1