But I don't know their values!

$\log a+\log b+\log c= \log(abc)$

$\log\left(\dfrac {{a}^{2}}{bc}\right)+\log\left(\dfrac {{b}^{2}}{ac}\right)+\log\left(\dfrac {{c}^{2}}{ab}\right)= \log \left( \dfrac {{(abc)}^{2}}{ab \times bc \times ca}\right)$

$\rightarrow \log 1$

$\log 1=0$

Answer:- $0$

$log(\dfrac {{a}^{3}}{abc})+log(\dfrac {{b}^{3}}{abc})+log(\dfrac {{c}^{3}}{abc})$

$loga^3 - logabc + logb^3 - logabc + logc^3 - logabc$

$3loga + 3logb + 3logc - 3log(abc)$

$= 3log(abc) - 3log(abc) = 0$

log((a^.b^2.c^2)/(bc.ab.ac))=log1=0