SOLUTION: Find the minor of the element equal to 7 in the matrix: [ 3 2 7 1 -2 4 5 3 -1] Thank you kindly.

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Question 985708: Find the minor of the element equal to 7 in the matrix:
[ 3 2 7
1 -2 4
5 3 -1]
Thank you kindly.
Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!



Figure. The minor of the
element equal 7 in the matrix

The minor of the element equal  7  is the determinant of the  2x2  sub-matrix shown in the  Figure.

It is  2x2  sub-matrix  %28matrix%282%2C2%2C+1%2C+-2%2C+5%2C+3%29%29,  and its determinant is  1*3 - 5*(-2) = 3 + 10 = 13.

Thus the minor of the element equal  7  is  13.

You can learn more from the lesson  Co-factoring the determinant of a 3x3 matrix  in this site.