Question

http://prntscr.com/20dk8l

Answer 1

It's 5

Answer 2

if you're using the FOIL method, you would get something like
10−510−−√+510−−√−5

Answer 3

err had to copy my answer from last time
\[10 - \sqrt{5}\sqrt{10} + \sqrt{5}\sqrt{10} -5\]

Answer 4

thank you both

Answer 5

Anytime!