= (√(2*81)-10√5)√2 + (5+√10)
= (√2√81-10√5)√2 + (5+√10)
= (9√2-10√5)√2 + (5+√10)
= 9(√2)^2 - 10(√5)√2 + 5 + √10
= 9(2) - 10(√10) + 5 + √10
= 18 - 10√10 + 5 + √10
= 23 - 10√10 + √10
= 23 - 9√10