r1-2r3,r2-3r3,r4-r3-7 7 -12 0-13 -3 -17 07 -2 7 3-2 -1 -4 1r3-3r4-7 7 -12 0-13 -3 -17 013 1 19 0-2 -1 -4 1按第4列展开-7 7 -12-13 -3 -1713 1 19r2+r3-7 7 -120 -2 213 1 19c3+c2-7 7 -50 -2 013 1 20按第2行...