(1)f(x1,x2,x3)=2+4n2+n3-41x2-8x1x3-4x2x3; (2)f(x1,x2,x3)=2x2+2n2+2x3-2x1x2-2x1x3-2x2x3 8.设A要反件B,则A可逆示并则示B可逆作这存A-1要反件B-1 9.设A要反件B,C要反件D则 B 0(1) f(x1, x2, x3) = x 2 1 + 4x 2 2 + x 2 3 − 4x1x2 − 8x1x3 − 4x2x3; (2) f(x1, x2, x3) = 2x 2 1 + 2x 2 2 + 2x 2 3 − 2x1x2 − 2x1x3 − 2x2x3. 8.  A H-W B, a A k
 a B k
￾e A−1 H-W B−1 . 9.  A H-W B, C H-W D a  A 0 0 C  H-W  B 0 0 D  . 9