Question

Solve the equation in the complex number system X^4-2x^2-3=0

Answer 1

$x^4-2x^2-3=0\\ x^4+x^2-3x^2-3=0\\ x^2(x^2+1)-3(x^2+1)=0\\ (x^2-3)(x^2+1)=0\\ x^2-3=0 \vee x^2+1=0\\ x^2=3 \vee x^2=-1\\ x=-\sqrt3 \vee x=\sqrt3 \vee x=-i \vee x=i$