Question

2. If ¡2x+3 = i, where i = V-1, then which of the

Answer 1

I assume you mean the equation

$i^{2x+3} = i$

Since i = √(-1), we have i⁴ = 1 and so i⁵ = i. Then 2x + 3 must be some multiple of 5.

Now just check for which of the given choices that this holds:

x = 16   ⇒   2x + 3 = 35   (yes)

x = 11   ⇒   2x + 3 = 25   (yes)

x = 10   ⇒   2x + 3 = 23   (no)

x = 14   ⇒   2x + 3 = 31   (no)