решите уравнения: 
(600- X)-92=126 
502-(217-X)=421 
871-(X+157)=385

2) Complete the sentences by changing the verbs in brackets into appropriate tense forms.
1 Tara has broken up with Tony. Now she ... Frank, (date)
2 Tara and Frank ... for two weeks, (date)
3 We didn't go for a walk because it... at the time, (rain)
4 The playing field was almost under water because it... for days, (rain)
5 This time next week, Anthony ... children how to abseil, (teach)
6 By the end of his stay in Mexico, Ben ... Spanish for a month, (learn)

 помогите пожалуста

Формула гемоглобина С2954 Н4516 N780 O806 S12 Fe4 (в мг)
В одной капле крови содержится 7ю25х10-3 г гемоглобина .
Сколько грамм железа можно из нее выделить?