題組內容
2 Let $A, B \in M_{n \times n}(\mathbb{R})$.
c. (5) If \( A \) is invertible then show that \( \operatorname{rank}(AB) = \operatorname{rank}(B) \).
2 Let $A, B \in M_{n \times n}(\mathbb{R})$.
c. (5) If \( A \) is invertible then show that \( \operatorname{rank}(AB) = \operatorname{rank}(B) \).