Question

Qual o valor de:
$a) log_{15}(3) + log_{15}(5) \\ b)log_{3}(72) - log_{3}(12) \\ c) log_{3}(81) - log_{2}(8)$

Me ajudem!! É uma urgência:(​

Answer 1

$\large\boxed{\begin{array}{l}\tt a)~\sf \ell og_{15}3+\ell og_{15}5=\ell og_{15}(3\cdot5)\\\sf=\ell og_{15}15=1\\\tt b)~\sf \ell og_372-\ell og_312=\ell og_3\bigg(\dfrac{72}{12}\bigg)\\\sf=\ell og_36=\ell og_3(2\cdot 3)=\ell og_32+\ell og_33\\\sf=\ell og_32+1\\\tt c)~\sf \ell og_381-\ell og_28=\ell og_{3^1}3^4-\ell og_{2^1}2^3\\\sf=\dfrac{4}{1}-\dfrac{3}{1}=4-3=1\end{array}}$