These strong animals help to carry things for   2).................  owners. The elephants go there for a month 4)........... year to have a rest.
2) they, them, their
4) every, once, this

Пожалуйста!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!замените М многочленом так, чтобы получилось тождество: М-(4ху+3у^2)=х^2+xy-y^2