Kunze Linear Algebra · Problem 1.6.8

Systems of Linear Equations

Mathematics — Methods · invertibility-2x2

Problem

Let A=[abcd].A = \begin{bmatrix} a & b \\ c & d \end{bmatrix}. Prove, using elementary row operations, that AA is invertible if and only if (ad−bc)≠0(ad - bc) \neq 0.

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