Question

Решите уравнение х^5-81х=0

Answer 1

 x^{5}-81x=0 
  x( x^{4} -81)=0;
 x=0;
 (x^{2} -9)( x^{2} +9)=0;
 x=+/-3 

Answer 2

$x( {x}^{4} - {3}^{4} ) = 0 \\ x( {x}^{2} - {3}^{2} )( {x}^{2} + {3}^{2} ) = 0 \\ x(x - 3)(x + 3)( {x}^{2} + 9) = 0 \\ x1 = 0 \\ x2 = 3 \\ x3 = - 3 \\ {x}^{2} = - 9 \: net \: resheniy$
3 корня.