Question

x^4-7x^2+6=0 помогите решить

Answer 1

Пусть t=x²
Тогда 
t²-7t+6=0
D = 7²- 6·4 = 25
$\left[\begin{array}{c}t = \frac{7 + 5}{2} \\t = \frac{7 - 5}{2}\end{array}$
$\left[\begin{array}{c}t = 6 \\t = 1\end{array}$
$\left[\begin{array}{c} x^{2} = 6 \\ x^{2} = 1\end{array}$
$\left[\begin{array}{c}x=-1\\x=1\\x=6\\x=-6\end{array}$