Здравствуйте) Помогите,пожалуйста с решением:

Четырехугольник ABCD вписан в окружность. Угол ABC равен 105 градусов, угол ADB равен 40 градусов. Найдите угол BAC.

В треугольнике АВС АС=ВС, угол С=120 градусом, АС=25 корней из 3 . Найти АВ.

1)Соотнесите формы глагола с характеризующими их названиями:

1)be+Ving                                                    

2)have Vз                                                    

3)V-ed                                                         

4)will V                                                         

5)V,Vs                                                          

a)Present Perfect

b)Present Progressive                                                               

c)Past Simple                                                                                        

d)Present Simple

e) Future Simple

2. Раскройте скобки, употребляя глагол в нужной форме: Present Simple, Present Progressive, Past Simple or Present Perfect.

1. Where is the old man living now? – He (live) with his married daughter. He usually (live) with her for six month every year. 2. He’s a night watchman. He works at night and (sleep) in the daytime. It’s noon, and he still (sleep). 3. I first (meet) George a month ago, and I (meet) him several times since then. 4. I usually (go) to bed before midnight. We are in September now, and we (do) a lot of work this year; we (do) a lot last year also. 6. What ‘s your brother doing? –He (do) the crossword in the newspaper. He (do) it every day. 7. He wants to buy a car, but first he must learn how to drive, so he (take) driving lessons. 8. I (write) to my parents a fortnight ago, but I’ve not had a reply, so I just (write) again. 9. He’s a very hard worker. He often (work) until midnight. It’s 11 p.m. now and he still (work).10. It’s 3 p.m. and he (not eat) anything today, but he (eat) a good dinner last night. 11. Is Mary ready to come out? – No, she still (dress). 12. I (read) this book several times. I first (read) it in 1997. 13. He often (read) detective stories; he (read) a very good one now. 14. She (not have) a holiday since 1999, but she (have) a very long holiday in 1998.

Докажите,что любая сторона треугольника меньше его полупериметра.
Оформите еще,пожалуйста.
Буду благодарна. 

сократите пожалуйста дроби (х+у)в квадрате - (х-у)в квадрате /x