решить уравнение x^4-8x^2-9=0

Назовите основные группы противоречий мирового развития в конце 19- начале 20 веков?

С какими из перечисленных веществ: Al, Hg, KOH, Cu(OH)2, NaNO3, BaCl2, CaCO3, HCl, H3PO4, CaO; реагирует раствор Fe2(SO4)3?

You’ve got a letter from your English pen-friend in which he/she wrote you about his/her future plans. He/she wants to become an actor. And your friend is sure that this profession will give him/her the opportunity to become famous and make a lot of money. Write a letter to your pen-friend in which say

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