Fixing latex in all translations

[chinmaySinghal]

#144
Fixed the equations in es, zh and ko. The Italian folder doesn't have the translated file yet.

[Atcold]

There are 3 issues currently tracked by #144.

• Correction in Week 02, Lecture part 2 #127 2020.03.24 02-2
• Fixing latex #157 2020.03.27 01-1
• Update 02-1.md #171 2020.03.28 02-1

You're fixing all of them?

[chinmaySinghal]

The fixes I've proposed are only for #157. es, it and ko do not have translated version for week 2 yet. When available, I can fix #171 too though. #127 requires translating, which can be done by the translators or if you want I can use google translate and do that too.

[Atcold]

Thank you. Updating only #157 state, then.