3√18+五分之一√50-四分之一√二分之一=

3√18+(√50)/5-√(1/2)/4= 3x3√2 + 5√2/5 - (1/√2)/4
= 9√2 + √2 - 1/(4√2) =10√2 - √2/ (4x2)
= ( 10-1/8) √2 = 79 √ 2 / 8
√2(1+√2)-1=√2+2-1 =√2+1
√48÷√3-√(1/2)×√12+√24= √(48/3) - √(12/2) +√24
= 4- √6 + 2√6
=4 +√6
(5+√10)(5√2-2√5)= 25√2 -10√5 + 5√20 - 2√50
= 25√2- 10√5+5x2√5- 2x5√2
= 25√2-10√5 + 10√5 -10√2
= 15√2