1 原理
对于 n n n个变量、 n n n个方程的线性方程组 { a 11 x 1 + a 12 x 2 + ⋯ + a 1 n x n = b 1 a 21 x 1 + a 22 x 2 + ⋯ + a 2 n x n = b 2 ⋯ ⋯ ⋯ a n 1 x 1 + a n 2 x 2 + ⋯ + a n n x n = b n , (1) \begin{cases} a_{11}x_1+a_{12}x_2+\cdots +a_{1n}x_n=b_1 \\ a_{21}x_1+a_{22}x_2+\cdots +a_{2n}x_n=b_2 \\ \cdots \cdots \cdots \\ a_{n1}x_1+a_{n2}x_2+\cdots +a_{nn}x_n=b_n\end{cases}\tag{1} , ⎩ ⎨ ⎧