# A quick question on determinants!

#### LaraCroft

1. 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) =___?

2. Homework Equations

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

3. The Attempt at a Solution

Related Calculus and Beyond Homework Help News on Phys.org

#### tiny-tim

Homework Helper
Hi LaraCroft!

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

then you can set about proving why

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