根号2（根号8-根号50+根号18）
=根号2(根号2^2*2-根号5^2*2+根号3^2*2)
=根号2(2根号2-5根号2+3根号2)
=根号2*0
=0
1/3根号0.36+1/5根号900
=1/3根号36/100+1/5根号9*100
=1/3*根号36/根号100+1/5*根号9*根号100
=1/3*6/10+1/5*3*10
=1/5+6
=31/5