Given:
[tex]x^4=1[/tex]Taking square root on both sides, We have
[tex]x^2=\pm1[/tex]A)
[tex]x^2=1[/tex][tex]x=\pm1[/tex]-1 and 1 are the real solutions of the given equation.
B)
[tex]x^2=-1[/tex][tex]x=\pm i[/tex][tex]x=i,-i[/tex][tex]i\text{ and -i are the imaginary solutions of the given equation.}[/tex]