źródło:
a) \sqrt[3]{9}*\sqrt[3]{3} = \sqrt[3]{27} = \sqrt[3]{{3^3}} = 3
b) 3\sqrt{18}+5\sqrt{12}-\sqrt{50}+\sqrt{27}=
=3\sqrt{9*2}+5\sqrt{4*3}-\sqrt{25*2}+\sqrt{9*3}=
=3*3\sqrt2+5*2\sqrt3-5\sqrt2+3\sqrt3=
=9\sqrt2+10\sqrt3-5\sqrt2+3\sqrt3=4\sqrt2+13\sqrt3