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Suppose that A and B are square matrices and that ABC is invertible. Show that each of A, B, and C is invertible.

User Utarid
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Answer:

Explanation:

Let A, B and C be square matrices, let
D = ABC. Suppose also that D is an invertible square matrix. Since D is an invertible matrix, then
det (D) \\eq 0. Now,
det (D) = det (ABC) = det (A) det (B) det (C) \\eq 0. Therefore,


det (A) \\eq 0


det (B) \\eq 0


det (C) \\eq 0

which proves that A, B and C are invertible square matrices.

User Chrisli
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