Find the determinants in Exercises by row reduction to echelon form.

Solution 9EConsider the determinant :To transform into echelon form, add first row to the third row. Now add -3 times the first row to the fourth row. Now add second row to the third row. Now factor out 7 from third row. Now add -7 times the third row to the fourth row. The resultant matrix is in echelon form.Now calculate determinant using cofactor...