Linear Algebra problem - matrices?

[LighterOfDoobies]

If A has rank r, then it has an r-by-r submatrix S that is invertible. Remove (m-r) rows and (n-r) columns to find an invertible submatrix S inside A, B, and C. You could keep the pivot rows and pivot columns:

A =
[1 2 3]
[1 2 4]

B =

[1 2 3]
[2 4 6]

C =

[0 1 0]
[0 0 0]
[0 0 1]

 

[tkhunny]

Excellent typing.

You tell me the rank of each one, then we can get started.