Is there any simpler method to do this

Question

anonymous · Answer

Find the value of the expression 
2x^3 + 2x^2 -7x + 72
at x = $$\frac{ 3 + 5\sqrt{-1} }{ 2 }$$

ganeshie8 · Answer

how did u arrive at this step ?

anonymous · Answer

This is not any step but rather the question itself
This is the main question

ganeshie8 · Answer

anonymous · Answer

yeah it would be iota  ok i will see the link

anonymous · Answer

so you know how to do it :)
hint for complex :-
(cos theta +i sin theta )^n=cos n theta +i sin n theta

ganeshie8 · Answer

but changing to polar is a pain here, better to work it algebraically

anonymous · Answer

answer is 4 the wolfram gives sth different

anonymous · Answer

yep that right |dw:1401285536758:dw|