Find all real number solutions x^4-x^2-12=0

Question

Stuck on this one. Can anyone help?

Answer 1

x^4-x^2-12=0

(x^2-4)(x^2+3)=0

x^2-4=0

(x-2)(x+2)=0

x-2=0

x=2 (real)

x+2=0

x=-2 (real)

x^2+3=0

x^2=-3 will yield imaginary roots