A matrix is invertible iff:
ASymmetric
BIts determinant is non-zero
CAll entries are non-zero
DIt is square
Answer & Solution
Correct answer: B. Its determinant is non-zero
Square matrix A invertible (i.e., has A⁻¹ with AA⁻¹ = I) iff |A| ≠ 0. Equivalently: rows (and columns) are linearly independent.
Related questions
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