2x根号x-x平方根号x立方分之1+6x根号4分之x
=2x根号x - x平方*(x平方分之根号x) + 6x*(2分之根号x)
=2x根号x - 根号x + 3x根号x
=4x根号x
根号49x - x分之4根号x立方
=7根号x - x分之4x根号x
=7根号x - 4根号x
=3根号x