Question 887314
x(exponent 4) + 2x(exponent 2) -8 =0
x^4+2x^2-8=0
(x^2+4)(x^2-2)=0
..
x^2+4=0
x^2=-4
x=±√-4=±2i
or
x^2-2=0
x^2=2
x=±√2