Mình cân bằng pt rồi bạn tự chọn tỉ lệ theo cặp chất nhé! :))

1. H₂SO₄ + K₂CO₃ \(\rightarrow\) K₂SO₄  + H₂O + CO₂\(\uparrow\)

2. Fe + 2HCl \(\rightarrow\) FeCl₂ + H₂

3, 2Al + 3PbCl₂ \(\rightarrow\) 2AlCl₃ + 3Pb

1. Lan said she was working in Hanoi then

2. Binh said he needed a new bicycle

3. Mary said her English teacher was very humorous

4. My younger brother said he didn't want to stay at home then

5. Binh said Mr.Thanh could speak two languages well

6. Miss Hang said she would go on a picnic to Nha Trang the next day

7. Tom said he didn't know who she was

8. Mai told us that it was raining heavily outside

9. He said to his friend that he had to go home then

10. Hoa said she couldn't go out after 8 p.m

________

II

1. Lan asked Hoa if she could speak French well

2. I asked Mai if she was free that night

3. Nhi asked Mai if she liked listening to pop music

4. She asked me if she lived near there

5. A tourist asked me if I could tell her the way to the nearest post office

Gọi đa thức dư là \(ax^2+bx+c\) (do số chia bậc 3 nên thương bậc 2 trở xuống)

\(\Leftrightarrow P\left(x\right)=\left(x-1\right)\left(x-2\right)\left(x-3\right)\cdot c\left(x\right)+ax^2+bx+c\\ \Leftrightarrow\left\{{}\begin{matrix}P\left(1\right)=a+b+c=2\\P\left(2\right)=4a+2b+c=3\\P\left(3\right)=9a+3b+c=5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=\dfrac{1}{2}\\b=-\dfrac{1}{2}\\c=2\end{matrix}\right.\)

Vậy đa thức cần tìm là \(\dfrac{1}{2}x^2-\dfrac{1}{2}x+2\)

1: \(=\dfrac{4\left(x-1\right)}{\left(x+1\right)^2}\cdot\dfrac{3\left(x+1\right)}{-20\left(x-1\right)}=\dfrac{-12}{20}\cdot\dfrac{1}{x+1}=\dfrac{-3}{5x+5}\)

2: \(=\dfrac{x^2-xy+y^2}{\left(x-y\right)\left(x+y\right)}\cdot\dfrac{\left(x-y\right)^2}{\left(x+y\right)\left(x^2-xy+y^2\right)}\)

\(=\dfrac{x-y}{\left(x+y\right)^2}\)

3: \(=\dfrac{1-4x^2-1}{1-2x}:\dfrac{4x^2-2x-4x^2}{2x-1}\)

\(=\dfrac{4x^2}{2x-1}\cdot\dfrac{2x-1}{-2x}\)

=-2x

1. I'd rather you didn't ask me that question

2. I haven't seen Bob seen I was in HCM City

3. He would rather read books than watch TV

4. It took Peter three hours to repaint his house

5. He asked me if I knew to speak English

6. We haven't met each other for ten years

7. The film was so boring that she fell asleep

8. The furniture was too expensive for me to buy

9. The weather is so good that they are going for a picnic

10. The coffee is too hot for me to drink

20 strong enough to carry that heavy box.

21 isn't hot enough to boil the kettle.

22 wasn't warm enough for us to go swimming.

23 swims skillfully.

24 a very good English learner.

25 swims well.

26 a very fast runner.

27 more interesting than plays.

28 more difficult than English.

29 as intelligent as Jill is

30 to have a friend like you

31 to smoke 20 cigarettes a day, but now he doesn't smoke any more.

32 enough to lift that heavy table.

a) áp dụng tính chất dãy tỉ số = nhau ta có:

y-x/2-3 =21/-1 =-21

x= -21.2=-42

y=-21 .3=-63

mình tính nhầm

vcl