Question

Решите уравнение X^4-7x^2+12=0

Answer 1

$x^4-7x^2+12=0\\x^2=t\geq 0\\t^2-7t+12=0\\\left \{ {{t_1+t_2=7} \atop {t_1t_2=12}} \right. \Rightarrow t_1=3,t_2=4,\\\left \ [ {{x^2=3} \atop {x^2=4}} \right. \left \ [ {{x=\pm\sqrt3} \atop {x=\pm \sqrt4}} \right. \left \ [ {{x=\pm\sqrt3} \atop {x=\pm 2}} \right.$