[tex]a). \sqrt{3} ( \sqrt{12} -2 \sqrt{27} )= \sqrt{3} (2 \sqrt{3} -2 \cdot 3 \sqrt{3} )= \sqrt{3} (2 \sqrt{3} -6 \sqrt{3} )= \\ = \sqrt{3} \cdot (-4 \sqrt{3} )=-4 \cdot 3=-12 \\ b).(3+ \sqrt{3} )(2+ \sqrt{3} )=3 \sqrt{3} +6+2 \sqrt{3} +3=5 \sqrt{3} +9[/tex]