3.2n – 4.2 n-2 = কত?

3.2ⁿ – 4.2 ^n-2= কত?

A 2ⁿ⁺¹

B 2^n-1

C 3

D 2ⁿ

Correct Answer: Option A

3 . 2ⁿ- 4 . 2^{n - 2}
= 3 . 2ⁿ - 2² . 2^{n - 2}
= 3 . 2ⁿ - 2^{2 + n - 2}
= 3 . 2ⁿ - 2ⁿ
= 2ⁿ (3 - 1)
= 2ⁿ . 2¹
= 2^{n + 1}