Substituting this into (2), we get
$2k + 1 \equiv 2 \pmod{3}$
$2k \equiv 1 \pmod{3}$
Multiplying by 2, we have $4k \equiv 2 \pmod{3}$, which simplifies to $k \equiv 2 \pmod{3}$.
Thus, $k = 3j + 2$ for some integer $j$.
Substituting this back into the expression
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