I would have used the difference of two squares twice:
Then, z = 1 and -1.
For the other two complex roots, we get:
Which you should be able to solve.
This isn't an equation. I suppose you mean
I wrote what I did about what you had not being an equation because you seem to have a problem with writing exactly what you mean- and it hurt you here. Those four numbers are the fourth roots- you have already solved the problem at this point:This is what i have done:
, , ,
and
, , ,
, , ,
P.S