F (x) = ( 3x^2 - 2x - 4 )/ ( 2x - 1 )
f ' (x) = [ ( 3x^2 - 2x - 4 )'•( 2x - 1 ) - ( 2x - 1 )'•( 3x^2 - 2x - 1 ) ] / ( 2x - 1 )^2 = [ ( 6x - 2 )( 2x - 1 ) - 2( 3x^2 - 2x - 1 ) ] / ( 2x - 1 )^2 = ( 12x^2 - 6x - 4x + 2 - 6x^2 + 4x + 2 ) / ( 2x - 1 )^2 = ( 6x^2 - 6x + 4 ) / ( 2x - 1 )^2