Question 1148752
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<pre>

    A = {{{(matrix(3,3, -7,2,-1,   0,-3,-1,  3,-4,-2))}}}.


Multiply the third column of the matrix A by 2 and add it to the second column. You will get the matrix B then


    B = {{{(matrix(3,3, -7,0,-1,   0,-5,-1,  3,-8,-2))}}}.


The basic property of the determinant is that under such transformations of the matrix, determinant remains the same:


    det(B) = det(A).


Now determinant B is easier to calculate than determinant A.  Omitting the zero terms,


     det(B) = (-7)*(-5)*(-2) - 3*(-5)*(-1) - (-7)*(-8)*(-1) = -29.    <U>ANSWER</U>
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Solved.