Question 989586
<pre>
I don't believe in just listing answers.  I believe in 
showing how to get them.

{{{x^4}}}{{{""=""}}}{{{1}}}

{{{x^4-1}}}{{{""=""}}}{{{0}}}

{{{(x^2-1)(x^2+1)}}}{{{""=""}}}{{{0}}}

{{{(x^""-1)(x^""+1)(x^2+1)}}}{{{""=""}}}{{{0}}}


{{{(x^""-1)(x^""+1)(x^2-(-1))}}}{{{""=""}}}{{{0}}}

{{{(x^""-1)(x^""+1)(x^2-i^2)}}}{{{""=""}}}{{{0}}}

{{{(x-1)(x+1)(x-i)(x+i)}}}{{{""=""}}}{{{0}}}

x-1=0; x+1=0;  x-i=0; x+i=0
  x=1;   x=-1;   x=i;   x=-i

Edwin</pre>