how do i work this out please?

Answer:
[tex]5 \sqrt{5} - 2 \sqrt{5} = 3 \sqrt{5} \\ 8 \sqrt{7} + 3 \sqrt{7} = 11 \sqrt{7} [/tex]
hope this helps.
Answer:
[tex]11 \sqrt{7} [/tex]
Step-by-step explanation:
[tex]8 \sqrt{7} + 3 \sqrt{7} [/tex]
[tex] \sqrt{7} (8 + 3) [/tex]
[tex]11 \sqrt{7} [/tex]