Brazil l can you solve this radical problem?? l Olympiad Mathematics

[@Sam_on_YouTube]

You made it more complicated than needed.
Assume y>0
√y+√-y=4
√y+i√y=4
(1+i)√y=4
√y=4/(1+i)
√y=4(1-i)/[(1+i)(1-i)]
√y=(4-4i)/2
√y=2-2i
y=(2-2i)^2
y=4+2*2*2i+4i*i
y=4+8i-4
y=8i
Assume y

[@novellobrancher9627]

👍👍👍

[@sergiykanilo9848]

( sqrt( y )+ sqtr( -y ) )^2 = y + 2iy - y = 2iy =4^2 =16
y ={+/-) i8