Answer:
-27
Step-by-step explanation:
It looks like you're trying to evaluate ...
[tex]\displaystyle 5^{\log_5{8}}-3^{\log_3{5}+\log_3{7}}=8-3^{\log_3{35}}=8-35=\boxed{-27}[/tex]
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The relevant rules are ...
b^(log_b(x) = x
log(a)+log(b) = log(ab)
