81x - 1 = 33x + 1 হলে x = ?

81^{x - 1} = 3^{3x + 1} হলে x = ?

A 1

B 3

C 4

D 5

Correct Answer: Option D

81^{x - 1} = 3^{3x + 1}
বা, (3⁴)^{x - 1} = 3^{3x + 1}
বা, 3^{4x - 4} = 3^{3x + 1}
বা, 4x - 4 = 3x + 1
বা, 4x - 3x = 1 + 4
∴ x = 5