QUESTION 4 Compute the determinant of the matrix by cofactor expansion. Compute the determinant of the matrix by row reduction. 1 2 5 3 6 9 -2 3-1Determinants Positions + - + ) Ex . - A = 1 15 0 + 2 4 - 1 6 0 - 2 0 Expand on Row 3 using cofactors. + 0 1 5 0 7 - ( - 2) 1 0 1 + 0 151 4 -1 1 2 -1 24 0 + 2 ( - 1 - 0 ) + 0 = - 2 A = 1 5 0 7 2 4 - 1 0 -2 0 1 0 - ( - 1 ) 1 5 + 0 10 - 21 - 2 - 0 = - 2 Ex. - 7 8 - 6 - 5 7 3 0 1- 5 7 A = 3 0 15 0 Az 0 0 0 0 2 4 - 1 - 2 O = 3 ( 2 ) 1 5 0 1 = 3 ( 2 ) ( 1 2 ) 1 0 2 4 - 1 2 -1 0 - 2 0 ) = 12 (-1-0) -12