b) 3²ⁿ⁻³ = 3²¹ : 3⁴
3²ⁿ⁻³ = 3²¹⁻⁴
3²ⁿ⁻³ = 3¹⁷
2n-3 = 17
2n = 20
n = 10
c) 5³ⁿ⁺¹ = 5²²
3n+1 = 22
3n = 21
n = 7
d) 7ⁿ⁺¹⁻⁴ = (7²)⁸
7ⁿ⁻³ = 7¹⁶
n-3 = 16
n = 19
e) 10²ⁿ⁺¹ : 5²ⁿ⁺¹ = 8⁹
(10:5)²ⁿ⁺¹ = (2³)⁹
2²ⁿ⁺¹ = 2²⁷
2n+1 = 27
2n = 26
n = 13
