How to find a determinant of a square matrix of order 3?

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Determinant of a square Matrix of order 3 
The value of the determinant of a square matrix of order 2 or greater than 2 is the sum of the products of the elements of any row or column with their corresponding cofactors. 
Consider a square matrix of order 3 
Let matrix A is equal to matrix 1 -2 4 -3 6 5 2 -7 9. Using the first row elements, we have cofactor A11 -1 to the power of 1 plus 1 into 6 into 9 minus of minus 7 into 5 i.e., equal to 54 minus of minus 35 i.e., equal to 89. 
Similarly, we can calculate the cofactors A12 and A13. 
Now determinant of matrix A is equal to 1 into 89 plus of minus 2 into 37 plus 4 into 9 i.e., equal to 89 minus 74 plus 36 is equal to 51. 
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Here is a problem for you to solve. You need to find the determinant of a 3 cross 3 matrix A by using the second row elements of the matrix. 
Find the cofactors A21 A22 A23 then calculate the determinant of the matrix. Use the OK button to check your answer and SOLVE button if you are unable to solve the problem. 
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