Question

Find the four complex roots of (z^2 + 2)^2 + 2 = z

I expanded it and got z^4+4z^2-z+6=0, not sure where to go from here

Answer 1

z^4+4z^2-z+6=0 is correct
then
https://www.mathportal.org/calculators/polynomials-solvers/polynomial-roots-calculator.php

Answer 2

note quartic method there
https://www.mathportal.org/formulas/algebra/solalgebric.php