Đáp án:
Bài `1`
` 343/125 = (7/5)^n`
` => (7^3)/(5^3) = (7/5)^n`
` => (7/5)^3 = (7/5)^n`
` => n = 3`
Bài `2`
` (2^(7).9^(3))/(6^(5).8^(2))`
` = (2^(7).(3^2)^3)/(2^(5).3^(5).(2^3)^2)`
` = (2^(7).3^(6))/(2^(5).3^(5).2^(6))`
` = (2^(7).3^(6))/(2^(11).3^(5))`
` = 3/(2^4) = 3/16`