let z=a+bi.
(a+2)^2=(a-2)^2
a=0
the equation becomes (2+bi)^n - (bi-2)^n = 0
((2+bi)(bi-2))^n - ((bi-2)(bi-2))^n = 0
(-b^2-4)^n - (bi-2)^(2n) = 0
now 2+bi and bi-2 has the same radius.
Let 2+bi=re^(iu). bi-2=re^(ipi/2-iu).
niu = nipi/2-niu+2ikpi
u = pi/4 + kpi/n