Hello, I am a beginner, I've written a method to calculate the unknown
arriere[D_, R_] := Module[{n, a, b, x},
a = D;
b = R;
n = Dimensions[a][[1]];
For[j = n, j >= 1, j--,
If[ a[[j, j]] == 0 , Break[]]
x[[j]] = b[[j]]/a[[j, j]];
For[i = 1, i <= j - 1,
i++
b[[i]] = b[[i]] - a[[i, j]]*x[[j]];
];
];
{x}];[/i][/i][/color]
but it returns me only the values ??of the input
k = {{1, 2, 3}, {0, -3, -6}, {0, 0, 1}}
l = {1, -3, 0}[/color]
arriere[k, l]
arriere[{{1, 2, 3}, {0, -3, -6}, {0, 0, 1}}, {1, -3, 0}]
