解法1.用初等行变换将(A,E)化为(E,A^-1)(A,E) =1 2 1 -2 1 0 0 00 5 3 -2 0 1 0 00 0 3 5 0 0 1 00 0 0 3 0 0 0 1r4*(1/3),r1+2r4,r2+2r4,r3-5r41 2 1 0 1 0 0 2/30 5 3 0 0 1 0 2/30 0 3 0 0 0 1 -5/30 0 0 1 0 0 0...