S = (x + 2)3 - 6x(x + 2) + (2x - 1)3 + 6x(2x - 1) - 9(x3 - 2)

S = ( x + 2 )3 - 6x( x + 2 ) + ( 2x - 1 )3 + 6x( 2x - 1 ) - 9( x3 - 2 )