помогите:* Крестьянская война под предводительством Е.И.Пугачева.вопрос определите на какой территории развернулась крестьянская война.

В арифметической прогрессии [tex]c_{5} = 16, c_{15} = 36[/tex]. Найдите [tex]S_{25}[/tex] (сумму первых 25 членов).

Мое решение:

[tex]d = (36 - 16)/10 = 2[/tex]

[tex]c_{1} = 16 - 2*4 = 8[/tex]

[tex]S_{25} = 25*8 + (2*25*24)/2 = 200 + 600 = 800[/tex]

В ответах 780. Можете ли вы найти ошибку в моем решении?

Read the text and match items A-G to the gaps 1-6. There is one item you do not need to use. Write your answers in the table below.

There are many different kinds of activities for us to enjoy nowadays. In fact, there is something for all personality types.

If  you are the brave, adventurous kind,

you can try skydiving or white-water rafting.

Many people are crazy about sports   like   these (1). Today we live in the 'extreme' sport world. We seek adventure instead of

(2). 

If  you are the quieter type, you may enjoy gardening or fishing. These activities are more relaxing 9 (3). Seeds sewn in the spring result in beautiful flowers that can brighten up your mood; fishing with friends can strengthen the relationship you have, or may just be a relaxing day out with a tasty supper at the end!

The imaginative may take up art classes or learn sculpture. In today's fast-paced world we all appreciate the opportunity to express

ourselves and take it easy (4) . Solitary

activities like knitting or stamp collecting, once considered to be old-fashioned, are becoming popular again.

Traditional team sports like football or basketball are great for developing team spirit and a sense of national pride. However, shy, reserved types prefer to watch them from the comfort of their couches rather than practise the sport itself. It is a pity(5).

 Today's pastimes are often linked to technology and may encourage us to be lazy. Surfing the Net or chatting online is a popular pastime for many but more sociable types prefer to go to the cinema or go to an exhibition (6).

Whatever we like to do in our free time, the main thing is to find something that we enjoy doing and be open to new experiences.

A  as sports like these have the ability to make us fit and strong

B  and they bring many rewards

C  because some people would rather go snowboarding

D  where they can be in direct contact with people

E  because of the adrenaline rush they get from them

F  after a hard day at the office

G staying at home and playing cards or board games

Как могут распологаться прямые на плоскости? 

Теорема о средней линии треугольника, без доказательства.

Цена  товара 760 тг

1)Цена повысилась на 15%.Какова последняя цена товара?

2)Цена снизилась на 30%.Какова последняя цена товара?