Answer:
Recall that:
[tex]\begin{gathered} \log _bx+\log _by=\log _b(xy), \\ \log _bx-\log _by=\log _b(\frac{x}{y})\text{.} \end{gathered}[/tex]
Therefore, Arjun used the properties incorrectly, he should´ve written:
[tex]\log _7x+\log _7y-\log _7z=\log _7(xy)-\log _7z=\log _y(\frac{xy}{z})\text{.}[/tex]
