Factoring quartic equation $$x^4+6x^2+25=0$$
How could I factor it into $(x^2-2x+5)(x^2+2x+5)=0$?
I got the result looking into horrible formulas on wikipedia, but I suppose there's a much easier way. Could you help me?

$$\underbrace{(x^2)^2+5^2+2\cdot x^2\cdot5}+(6-10)x^2=(x^2+5)^2-(2x)^2$$
