If $|A| = 4$ for an invertible matrix $A$, then $|A^{-1}|$ equals:
A$16$
B$\tfrac{1}{4}$
C$1$
D$4$
Answer & Solution
Correct answer: B. $\tfrac{1}{4}$
|A⁻¹| = 1/|A| = 1/4, since |A|·|A⁻¹| = |I| = 1.
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