сократить дробь (5а^2+19a-4)/(1-25a^2)

Задайте общие альтернативные специальные и разделительные вопросы к предложениям:

1. Yesterday the lesson began at 9 o"clok.

2. You were at the theatre yesterday.

3. His sister likes coffee.

4. He will go to the exhibition next Sunday.

5. They are drinking tea now.

6. His children go to bed early. 

У треугольника ABC провели высоты AP и BH. Докажите, что AP=BH, если PC=HC.