tolong rumusnya ya :V

4ˣ⁺² + 7. 2ˣ⁺⁴ = 128
4ˣ⁺² + 7 . 2ˣ⁺² . 2² = 128
4ˣ⁺² + 7 . 2ˣ⁺² . 4 = 128
4ˣ⁺² + 28. 2ˣ⁺² = 128

Misal
2ˣ⁺² = a

a² + 28a = 128
a² + 28a - 128 = 0
(a + 32)(a - 4) = 0

a + 32 = 0
a = -32 ( tidak memenuhi)

a - 4 = 0
a = 4

2ˣ⁺² = 4
2ˣ⁺² = 2²
x + 2 = 2
x = 2 - 2
x = 0

maka
2ˣ⁺¹ = 2⁰⁺¹
       = 2¹
       = 2

Jawaban D