Ответ:

x1 = -5

x2 = 0

x3 = 5

Детальніше нижче.

Объяснение:

[tex]x^4-25x^2=0\\x^2(x^2-25)=0\\\left \{ {{x^2=0} \atop { x^2-25=0}} \right. \\\left \{ {{x^2=0} \atop {x^2=25}} \right.\\ x=0\\x=-5\\x=5[/tex]