Answer:
[tex]5 \sqrt{3} [/tex]
Step-by-step explanation:
[tex] \rm - 8 \sqrt{3} + 13 \sqrt{3} [/tex]
Add 13 and -8
[tex] \implies\rm \: (13 - 8) \sqrt{3} [/tex]
[tex] \implies\boxed{\rm \: 5 \sqrt{3} }[/tex]