Answer:
[tex]\large\boxed{-\sqrt{12}+3\sqrt3=\sqrt3}[/tex]
Step-by-step explanation:
[tex]-\sqrt{12}+3\sqrt3=-\sqrt{4\cdot3}+3\sqrt3\qquad\text{use}\ \sqrt{ab}=\sqrt{a}\cdot\sqrt{b}\\\\=-\sqrt4\cdot\sqrt3+3\sqrt3=-2\sqrt3+3\sqrt3=(-2+3)\sqrt3=1\sqrt3=\sqrt3[/tex]
