Merge pull request #97 from MUlt1mate/master

Коррекция #86 ch28
re #56 Удалил оригинал
Update chapter-28.md

re #86
Merge pull request #98 from SavinaMarina/patch-7

Update chapter-28.md
Update chapter-29.md
Merge pull request #99 from SavinaMarina/patch-8

Update chapter-29.md