How Do Row Operations Affect Matrix Determinants?

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SUMMARY

The discussion focuses on the effects of row operations on matrix determinants, specifically addressing two scenarios: multiplying a row by a scalar and swapping rows. It is established that if the determinant of a 3 x 3 matrix A is 10, multiplying the third row by 8 results in a determinant of det(B) = 80. Additionally, for a 5 x 5 matrix A with a determinant of 9, swapping the second and fourth rows leads to a determinant of det(C) = -9, as row swaps invert the sign of the determinant.

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Homework Statement


If the determinant of a 3 x 3 matrix A is det(A) = 10, and the matrix B is obtained by multiplying the third row by 8, then det(B) = ___?

If the determinant of a 5 x 5 matrix A is det(A) = 9, and the matrix C is obtained from A by swapping the second and fourth rows, then det(C) =___?

Homework Equations



Ok, so do I use a generic matrix, or what? SO confused...

The Attempt at a Solution

 
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Hi LaraCroft! :smile:

Useful tip: write out a few matrices (easy ones, with lots of zeros :wink:), and see what happens …

then you can set about proving why :smile:
 

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