Question

Help: Find four solutions in the Complex numbers...

Answer 1

let x² = a
\[a^2-3a-4=0\]\[(a+1)(a-4)=0\]\[a=1,~~4\]hence you get \[x=~±i,~±2\]

Answer 2

I mean a = -1 and 4

Answer 3

I got: x=i,-i,2,-2

Answer 4

Same as @SolomonZelman