Đáp án:
a) `(1/3)^m = 1/81`
`→(1/3)^m = 1^4/3^4`
`→(1/3)^m = (1/3)^4``
`→m=4`
Vậy `m = 4 `
b) `-512/343 = ( -8/7)^n`
`→ {(-8)^3}/7^3 = ( (-8)/7)^n`
`→ ((-8)/7)^3=( (-8)/7)^n`
`→ n = 3`
Vậy `n=3`
c) `-32/(-2)^n = 4`
`→(-2)^5/(-2)^n=(-2)^2`
`→5-n=2`
`→n=5-2=3`
Vậy `n=3`