Đáp án:
`(5.4^15 .9^9 - 4 .3^20 .8^9)/(5.2^9 - 7 .2^29 .27^6)`
`= (5.(2^2)^15 . (3^2)^9 - 2^2 .3^20 .(2^3)^9)/(5.2^9 - 7 .2^29 .(3^3)^6)`
`=(5 .2^30 .3^18 - 2^2 .3^20 .2^27)/(5.2^9 - 7.2^29 .3^18)`
`= (5.2^30 .3^18 - 2^29 .3^20)/((5.2^9 - 7.2^29 .3^18)`
`= (2^29 .3^18 (5.2 - 3^2))/(2^9 (5 - 7.2^20 .3^18))`
`= (2^20 .3^18 .1)/(5 - 7.2^20. 3^18)`
`= (2^20 .3^18)/(5 - 7.2^20. 3^18)`
`= -1/7`