Đk: $a,b>0,\ne1$
$\log_ab=\dfrac{3}{2}\Rightarrow a^{\dfrac{3}{2}}=b$
$\Rightarrow a=b^{\dfrac{2}{3}}={\sqrt[3]b}^2$
$\log_cd=\dfrac{5}{4}\Rightarrow c^{\dfrac{5}{4}}=d$
$\Rightarrow c=d^{\dfrac{4}{5}}={\sqrt[5]d}^4$
$\Rightarrow a-c={\sqrt[3]b}^2-{\sqrt[5]d}^2$
$=({\sqrt[3]b}-{\sqrt[5]d}^2)({\sqrt[3]b}+{\sqrt[5]d}^2)=9$
$\Rightarrow {\sqrt[3]b}-{\sqrt[5]d}^2=1$ và ${\sqrt[3]b}+{\sqrt[5]d}^2=9$
$\Rightarrow {\sqrt[3]b}=5$ và ${\sqrt[5]d}^2=4$
$\Rightarrow b=125,c=32 $
