11)
a) x² + 1/9 = 5/27 . 3
x² + 1/9 = 5/9
x² = 5/9 - 1/9
x² = 4/9
x² = (2/3)² hoặc x² = (-2/3)²
x = 2/3 hoặc x = -2/3
b) (x + 2).(1/2)¹⁹ = (1/2)²²
x + 2 = (1/2)²² : (1/2)¹⁹
x + 2 = (1/2)³
x + 2 = 1/8
x = 1/8 - 2
x = -15/8
c) (3/7)³⁷ : (3/7)^(2x) = (3/7)³⁵
37 - 2x = 35
2x = 37 - 35
2x = 2
x = 2 : 2
x = 1
d) (4/5)³⁵ . (4/5)^(3x - 2) = 4³⁸/5³⁸
35 + 3x - 2 = 38
33 + 3x = 38
3x = 38 - 33
3x = 5
x = 5/3