Answer:
16.....................................
- 6⁹*6ⁿ = 6¹²
- 6⁹⁺ⁿ = ¹²
- 9 + n = 12
- n = 3
17.....................................
- 7⁸/7ⁿ = 7³
- 7⁸⁻ⁿ = 7³
- 8 - n = 3
- n = 5
18.....................................
19.....................................
- 1/10⁵ = 10ⁿ
- 10⁻⁵ = 10ⁿ
- -5 = n
- n = -5
20.....................................
- (8²)ⁿ = 8¹²
- 8²ⁿ = 8¹²
- 2n = 12
- n = 6
