If $A = [- 2 1 31]$ then $∣ A^{- 1} ∣ = ?$

- 5

\frac{- 1}{5}

\frac{1}{25}

25

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Elijah Discussed

A = [- 2 1 31]

then

∣ A^{- 1} ∣ = ?

6 mins ago

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6 mins ago

Text solutionVerified

A A^{- 1} = I \Rightarrow ∣ A A^{- 1} ∣ = ∣ I ∣ \Rightarrow ∣ A ∣ \cdot ∣ A^{- 1} ∣ = 1 \Rightarrow ∣ A^{- 1} ∣ = \frac{1}{∣ A ∣}

∣ A ∣ = ∣ ∣ - 2 1 31 ∣ ∣ = (- 2 - 3) = (- 5) \Rightarrow ∣ A^{- 1} ∣ = \frac{- 1}{5}

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