 Hello and welcome to the session. Let us understand the following problem today. Write minus and co-factors of the following element in the determinant. We have 1, 0, 0, 0, 1, 0, 0, 0, 1. Now let us write the solution. Miner of the element A11 that is this element is equal to M11 which is equal to the determinant 1, 0, 0, 1 which is equal to 1. Now, minor of the element A12 is equal to M12 which is equal to determinant 0, 0, 0, 1 which is equal to 0. Now, minor of the element A13 is equal to M13 which is equal to 0, 1, 0, 0 which is equal to 0. Similarly, minor of the element A21 is equal to M21 which is equal to the determinant 0, 0, 0, 1 which is equal to 0. Now, minor of the element A22 is equal to M22 which is equal to 1, 0, 0, 1 which is equal to 1. Now, minor of the element A23 is equal to M23 which is equal to 1, 0, 0, 0 which is equal to 0. Now, minor of the element A33 is equal to M33 which is equal to 1, 0, 0, 1 which is equal to 1. Now, minor of the element A31 is equal to M31 which is equal to 0, 0, 1, 0 which is equal to 0. And last, minor of the element A32 is equal to M32 which is equal to 1, 0, 0, 0 which is equal to 0. Now, let us find the cofactors. Cofactor of A11 is equal to A11 which is equal to minus 1 to the power 1 plus 1 M11 which is equal to minus 1 to the power square into 1 which is equal to 1. Cofactor of A12 is equal to A12 which is equal to minus 1 to the power 1 plus 2 M12 which is equal to minus 1 to the power cube into 0 which is equal to 0. Cofactor of A13 which is equal to A13 which is equal to minus 1 to the power 1 plus 3 M13 which is equal to minus 1 to the power 4 into 0 which is equal to 0. Now, cofactor of A21 is equal to A21 which is equal to minus 1 to the power 2 plus 1 M21 which is equal to minus 1 to the power 3 into 0 which is equal to 0. Now, cofactor of A22 is equal to A22 which is equal to minus 1 to the power 2 plus 2 M22 which is equal to minus 1 to the power 4 into 1 which is equal to 1. Now, cofactor of A23 is equal to A23 which is equal to minus 1 to the power 2 plus 3 M23 which is equal to minus 1 to the power 5 into 0 which is equal to 0. Cofactor of A31 is equal to A31 which is equal to minus 1 to the power 3 plus 1 M31 which is equal to minus 1 to the power 4 into 0 which is equal to 0. Now, cofactor of A32 which is equal to A32 which is equal to minus 1 to the power 3 plus 2 M32 which is equal to minus 1 to the power 4 into 0 which is equal to 0. Now, last one is cofactor of A33 which is equal to A33 which is equal to minus 1 to the power 3 plus 3 M33 which is equal to minus 1 to the power 6 into 1 which is equal to 1. Now, the required answers are M11 is equal to 1, M12 is equal to 0, M13 is equal to 0, M21 is equal to 0, M22 is equal to 1, M23 is equal to 0, M31 is equal to 0, M32 is equal to 0 and M33 is equal to 1. Now, cofactors A11 is equal to 1, A12 is equal to 0, A13 is equal to 0, A21 is equal to 0, A22 is equal to 1, A23 is equal to 0, A31 is equal to 0, A32 is equal to 0, A33 is equal to 1. This is our required answer. I hope you understood the problem. Bye and have a nice day.