It is required to combine the radicals which can be done as follows:
[tex]\begin{gathered} 5\sqrt[]{27}-17\sqrt[]{3}=5\sqrt[]{3\times3\times3}-17\sqrt[]{3} \\ =5\times3\sqrt[]{3}-17\sqrt[]{3} \\ =15\sqrt[]{3}-17\sqrt[]{3} \\ =(15-17)\sqrt[]{3} \\ =-2\sqrt[]{3} \end{gathered}[/tex]
Option D is correct.
