Question 772666
sqrt{1/5} = [sqrt(5)]/5
sqrt(80) = sqrt(16 * 5) = 4sqrt(5)

sqrt(1/5) + sqrt(80) = (sqrt(5))/5 + 4* sqrt(5) = (1/5 + 4)* sqrt(5) 

= (21/5)*sqrt(5)

Hope it helps you!

John10