Question

2х^4-17х^2-9=0
срочно плиз у меня кр

Answer 1

x^2=t
2t^2-17t-9=0
D=17^2+2*9*4=361=19^2
T1=17+19/2=9
T2=17/19/4=-1/2 - не уд усл
x=3;-3

Answer 2

$2x^4-17x^2-9=0;\ x^2=t;\ 2t^2-17t-9=0;\ D=17^2-4cdot2cdot(-9)=361=(pm19)^2;\ t_1=frac{17-19}{2cdot2}=-frac24=-frac12;\ t_2=frac{17+19}{2cdot2}=frac{36}{4}=9;\ x_1=-sqrt{t_2}=-sqrt9=-3;\ x_2=3.$