IMC 2009 · Problem 2

Day 116th IMC · Budapest, Hungary

Statement

Let AA, BB and CC be real square matrices of the same size, and suppose that AA is invertible. Prove that if (AB)C=BA1(A-B)C = BA^{-1}, then C(AB)=A1BC(A-B) = A^{-1}B.

Official solution

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