Respuesta :

crisforp
x^2 + 2x - 8 = 2x + 1 ;
x^2 - 9 = 0 ;
( x - 3 )( x + 3 ) = 0 ;
x - 3 = 0 or x + 3 = 0 ;
x = 3 or x = - 3 .