Question

⇓⇓⇓⇓⇓⇓⇓⇓⇓ Смотри вложение ⇓⇓⇓⇓⇓⇓⇓⇓⇓

Answer 1

m<0, m-n<0,

$sqrt{(m-n)^2}-sqrt{9m^2}=|m-n|+3|m|=-(m-n)-3(-m)=n-m+3m=n+2m$