2log39×log381−2log5625\frac{2\log_{3} 9 \times \log_{3} 81^{-2}}{\log_{5} 625}log56252log39×log381−2
= 2log332×log3(34)−2log5(54)\frac{2\log_{3} 3^{2} \times \log_{3} (3^{4})^{-2}}{\log_{5} (5^{4})}log5(54)2log332×log3(34)−2
= 4log33×−8log334log55\frac{4\log_{3} 3 \times -8\log_{3} 3}{4\log_{5} 5}4log554log33×−8log33
= -8.
