What is the determinant of the coefficient matrix of the system

Hence, the determinant of the coefficient matrix of the system is:

                                            65

We are given a system of linear equation in terms of variable x,y and z as:

Hence, the coefficient matrix that is obtained with the help of these system of equation let us denote by A is:

Now let us find the determinant of the matrix by expanding along row 1 as:

              Hence, the determinant is:

                                    65

sorry, i don't know i just need points, i'm new here. chao

found it xd it ok yt