Question

$x^{3}$-8$x^{2}$+8x-1=0

Answer 1

(х³-1) - (8х²-8х)=0
(х-1)(х²+х+1) - 8х(х-1) =0
(х-1)(х²+х+1-8х)=0
(х-1)(х²-7х+1)=0 ⇒ 
х-1=0 или х²-7х+1=0 ⇒ Д=7²-4=24 ⇒х₂ =(7+4√6) 2   х₃=(7-4√6) 2
х₁=1 ,