найдите 15 член арифметической прогрессии 9, 5, 1;...

Чем, окислителем или востановителем являются атомы или ионы водорода 

Fe2 O3 + 3H2 = 2Fe + H2O

3-5(х+1)=6-4х

Вставьте в предложения speak, tell или say.

1)She*ll ... us about her visit to Samara.

2)Brian ... me that he didn*t like the Science lesson.

3)"Don*t ask too many qiestions," my father ... .

4)French students ... English well.

5)The doctor ... that I must drink a lot of carrot juice.

6)"Can I ... to Mary, please?"-"I*m afraid she is not at home."