[tex]\displaystyle 4 \sqrt{12} - \sqrt{27} + \sqrt{75} =x \sqrt{3} \\ 4 \cdot 2 \sqrt{3} -3 \sqrt{3} +5 \sqrt{3} =x \sqrt{3} \\ 8 \sqrt{3} -3 \sqrt{3} +5 \sqrt{3} =x \sqrt{3} \\ 10 \sqrt{3} =x \sqrt{3} \\ x= \frac{10 \sqrt{3} }{ \sqrt{3} } \\ x=10[/tex]