# Why the restriction for u?

Algebra Level 4

$\large A = \begin{vmatrix}u & 2 & -1 \\ -1 & 1 & 2 \\ 2 & -1 & 1 \\ \end{vmatrix}$

If $$\det(adj(adj(A))) = 23^4$$, then what is the possible integral value of $$u \ ?$$

Note

• $$u \neq -\dfrac{11}{3}$$

• $$u \in \mathbb{R}$$

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