Схожість і відмінність іменника і прикметника

В керосин погружён кусок железа массой 500 грамм. Опредилите выталкивающую силу, если плотность железа 7900 кг/м^3, плотность керосина 820 кг/м^3

Проверьте, пожалуйста, сочинение на английском. Если есть ошибки в грамматике или с построении предложения или в употреблении слов, пожалуйста, исправьте их.

English for me.

There are many countries in the world are speaking on their own  language, which is used by all population. Among all languages we have the international languages as English, Germany, Italian, Spanish, Franch, Chinese, Spainish and exrt..

Nowadays English is played an important role in the business, science, medicine and technology. It is a language of diplomatic, communication and international relations. Every day English become more popular in other place.

If you  know a lot of  the foreign languages, you will have many opportunities. They are looking as an entrance in the world of  finance. Now, all kinds of jobs demand ownership of two language.

As for me, English is a very important language in my life, because it gives me for another chance to find the best job and open my outlook and knowledges. Now I study English at school. But it isn’t easy for me and I try  learning it. I never give up, because English is very  useful in the future.

решите уравнение (х-5)(х+5)-(х+(х-1)=9х