Question

.


.


.Factorise ( x^6 - 7x^3 - 8 )

Answer 1

here is your answer....

Answer 2

Heya !!




X^6 - 7X³ - 8




Putting X³ = Y , we get :



( X6 - 7X³ - 8 ) = (Y² - 7Y - 8 ) , where X³ = Y






=> Y² - 8Y + Y - 8



=> Y ( Y - 8 ) +1 ( Y - 8 )




=> ( Y - 8 ) ( Y + 1 )




=> ( X³ - 8 ) ( X³ + 1 )






=> [ (X)³ - (2)³ ] [ ( X)³ + (1)³ ]




=> [ (X - 2 ) ( X² + 2X + 4 ) ] ( X + 1 ) ( X² - X+1 )]



=> ( X - 2 ) ( X +1 ) ( X² + 2X + 4 ) ( X² - X + 1 ).



Hence,



X6 - 7X³ -8 = ( X- 2 ) ( X+ 1 ) ( X² + 2X+4 ) (X² - X + 1 ).