If x = 21/3 + 22/3, then the value of x3 − 6x is
x 3 -6x
= (21/3 + 22/3 )3 - 6( 21/3 + 22/3 )
=[ 2 + 22 + 3 .21/3 . 22/3 (21/3 + 22/3 ) ] - 6 ( 21/3 + 22/3 )
= 6 + 6 ( 21/3 + 22/3) - 6(21/3 + 22/3)
= 6
If x = 21/3 + 22/3, then the value of x3 − 6x is
x 3 -6x
= (21/3 + 22/3 )3 - 6( 21/3 + 22/3 )
=[ 2 + 22 + 3 .21/3 . 22/3 (21/3 + 22/3 ) ] - 6 ( 21/3 + 22/3 )
= 6 + 6 ( 21/3 + 22/3) - 6(21/3 + 22/3)
= 6