Đáp án:
a, `(1/3)^m = 1/81`
`(1/3)^m = (1/3)^4`
`⇒ m = 4`
b, `-512/343 = (-8/7)^n`
`(-8/7)^3 = (-8/7)^n`
`⇒ n = 3`
c, `-32/( (-2)^n)=4`
`⇒ (-2)^n =-32 : 4 = -8`
`⇒ (-2)^n =(-2)^3`
`⇒ n =3`
d, `8/(2^n) = 4`
` 2^n = 8 : 4 = 2`
`2^n =2^1`
`⇒ n = 1`
e, `(1/2)^(2n - 1) = 1/8`
`(1/2)^(2n - 1) = (1/2)^3`
`⇒ 2n - 1 = 3`
` 2n = 3 + 1 = 4`
` n = 4 : 2 = 2`