I am confused on how you would this problem?

This is a minor matrix problem and I have not idea how you go about doing this problem.I had look at my textbook and the glorious khan academy. I think it how khan academy showed where go though many possibles which was way to confusing to explain.So can some point me to the right direction?(Problem is in the Image)

Attachment image

2 Answers

Relevance
  • 1 month ago

    I can't draw the brackets around matrices on here, but I thought it was the following:

    .1 .. -7 ... 2

    .4 ... 8 .. -9

    -8 ... 7 ... 3

    M₁₃ is the determinant of the minor matrix made by removing row 1 and column 3 from the original matrix. In this case, that minor matrix is

    .4 .. 8

    -8 .. 7

    which has determinant

    (4 * 7) - (8 * -8)

    = 28 - (-64)

    = 92

    M₁₃ = 92

    • Login to reply the answers
  • 1 month ago

    M1,3 = 2*(24-(-9*7)) = 174 ANS If Mx,y is assumed.

    I'm not familiar with the notation M1,3.  Anyway it appears you left the 2, which is at (1,3) off the minor calculation.

    • ...Show all comments
    • Alan
      Lv 7
      1 month agoReport

      Yes, in finding the determinint, you multiply by 2*(-1)^(r+c) = 2*(-1)^(3+1) =  2  
      but the definition of minor doesn't include this part.   C_1,3 =   2*(-1)^(r+c)* M_1_3  
      where C = cofactor and M = minor 

    • Login to reply the answers
Still have questions? Get your answers by asking now.