If you want you CAN get a proper complex number for this square root, but it will be in terms of sines and cosines.
But wolfram alpha gives out this...
Wolfram doesn't give out a solution for this, and I wanted to know how was it done...
Any idea how it was done?
factorise3iu^2+26iu+4u^2+3i-4 - Wolfram|Alpha