n元线性方程组AX=b有唯一解的充分必要条件是 r(A) = r(A,b) = nr(A) = n 并不能保证 r(A) = r(A,b) 比如 增广矩阵 =1 1 10 1 10 0 1r(A)=2, r(A,b)=3
