Вопрос по математике:

Есть ли бесконечное множество натуральных чисел n, являющихся полными квадратами, что число 2n+1 тоже полный квадрат

Вопрос по геометрии:

Вопрос по экономике:

Вопрос по английскому языку:

Exercise 4. Use there and the correct form ofbe to complete the sentences.

1. In Britain … several mobile phone networks.

2. … different operators like Virgin Mobile and the others.

3. I think … a bug in this software.

4. … a spare power point in the workstation.

5.… two buttons and a scroll wheel on a mouse.

6.… a wireless network in our office.

7. Unfortunately … a problem with the print quality.

8. As is known, … two types of page orientation - portrait and landscape.

9. … an extension cable in case the wire is too short.

10. … six people in the project team.

11. … many computers that provide a web-based backup.

12. Obviously … more choice online but you can see things better in a shop.

Вопрос по алгебре: