Jawab:
[1a]  x = ⁵/₂
[1b]  x = -5
[1c]  x = (2 ln 3 - 3 ln 2) / ln 3
[1d]  x = ⁹/₂
[1e]  x = 1
[1f]   x = -2

Penjelasan:
[1a]  4ˣ⁺¹ = 128
(2²)ˣ⁺¹ = 2⁷
2(x+1) = 7
2x + 2 = 7
2x = 7 - 2
2x = 5
x = ⁵/₂

[1b]  2ˣ = ¹/₃₂
2ˣ = 32⁻¹
2ˣ = (2⁵)⁻¹
2ˣ = 2⁻⁵
x = -5

[1c]  3²⁻ˣ = 8
2-x = ³log8
x = 2 - ³log8
x = ³log9 - ³log8
x = (ln 9 / ln 3) - (ln 8 / ln 3)
x = (ln 9 - ln 8) / ln 3
x = (ln 3² - ln 2³) / ln 3
x = (2 ln 3 - 3 ln 2) / ln 3

[1d]  3²ˣ⁺¹ = 81ˣ⁻²
3²ˣ⁺¹ = (3⁴)ˣ⁻²
2x + 1 = 4(x-2)
2x + 1 = 4x - 8
4x - 2x = 1 + 8
2x = 9
x = ⁹/₂

[1e]  10²⁻³ˣ = 10⁵ˣ⁻⁶
2-3x = 5x-6
5x+3x = 2+6
8x = 8
x = 1

[1f]  ¹/₂₅ = 25⁻¹
x²-5x+7 = -1(x-x²-15)
x²-5x+7 = -x+x²+15
x²-x²-5x+x = 15-7
-4x = 8
x = ⁸/₋₄
x = -2

(xcvi)