Вопрос по математике:

Решить систему уравнений

{х-у=1,4^(2х-3у)=1

Вопрос по физике:

Вопрос по химии:

1. Плотность 25,36%-го раствора гидроксида калия равна 1,24 г/мл. Сколько молей KОН находится в 5 л раствора? Чему равны моляльность раствора, титр и мольные доли растворителя и растворенного вещества? 

Вопрос по английскому языку:

1.Open the brackets and put the verbs into the correct past tense:

1. Steve (to work) on his computer for two hours before it (to break down).

2. I (to mop) the floor while my brother was cutting the grass.

3. I (not can) find my umbrella, but then I (to remember) that my sister (to take) it to school.

4. You (to visit) your Granny two weeks ago?

5. Sam was really happy because he (to pass) all his exams.

6. Greg (not to answer) the phone because he (to take) a shower

2.

a) Change the sentences into the Passive:

1. Dave always organizes the school disco.

2. The police have arrested the driver.

3. Where will they hold the tennis tournament?

4. Bill and Sue are decorating our house.

5. The thief had taken the painting before the guard woke up.

b) Open the brackets, using the Passive Voice:

1. The Eiffel Tower ……. (to visit) by about six million people each year.

2. The exhibits in the museum mustn’t ……. (to touch).

3. Luckily, the fire ……. (to put out) before anyone got hurt.

4. A new swimming pool ……. (to build) in the leisure centre last month.

5. The floor ……. (to clean) when she came

3.Read the sentences. Choose one other sentence which means the same.

1. We are paying an artist to paint a new picture for the living-room.

a) We are having an artist painted for the living-room.

b) We are having a new picture painted for the living-room.

2. Dad has asked someone to do a sculpture for our garden.

a) Dad is having a sculpture done for our garden.

b) Dad has done a sculpture for our garden.

3. Our art teacher arranged for our pictures to be hung in the local art gallery.

a) The local gallery got our picture hung by our art teacher.

b) Our art teacher got our pictures hung in the local gallery.

4. A local architect has been asked to design a new restaurant for McBurger’s.

a) McBurger’s are having their new restaurant designed by a local architect.

b) A local architect is having a new restaurant designed by McBurger’s.

5. They have asked someone to write some music especially for their wedding.

a) They are having their wedding written especially for someone.

b) They are having some music written especially for their wedding.

4.: Fill in the gaps with the correct preposition:

1. I was brought ……. to respect the law.

2. Peter has fainted, try to bring him ……. .

3. These pictures bring ……. sad memories.

4. She's bringing ……. good money selling houses.

5. Tom has brought ……. another new book

Вопрос по химии:

дописать реакции ионного обмена в молекулярном ионном и ионно-сокращенном видах.

Cделайте вывод о необратимости или обратимости реакции

а) K2S+Cd(NO3)2-->

б) NH4CIO3+Sr(OH)2-->

с) Mg(OH)2+HNO3-->