b: Tọa độ giao là:

5x-4=2x+2 và y=2x+2

=>x=2 và y=6

c: Vì (d2)//d nên (d2): y=2x+b

Thay x=1 và y=3 vào (d2), ta được:

b+2=3

=>b=1

2. There used to have many old buildings 10 years ago

3. I wish a new mall didn't build

4. I have had this wardrobe since my wedding day

5. She hasn't been seen for two years

2. There used to be many old buildings 10 years ago.

3. I wish a new mall weren't built here.

4. I have bought this wardrobe since my wedding day.

5. She hasn't been seen (by me) for two years.

Mary if she could speak some foreign languages
Lan if she was going to visit her aunt the day after
what I was doing
how she was feeling then
what I usually did in my free time
why he why he didn't come there to meet her
why I was so lazy and naughty
like playing soccer, don't you?
goes to school late, doesn't he?
can swim very well, can't you?
is going to the party, isn't she?
was published in Germany in 1550, wasn't it?
are sold all over the world, aren't they?
have been built this year, haven't they?
was given a book, wasn't he?
was bought by Mrs Brown yesterday, wasn't she?
is used every day, isn't it?
be beautiful sights in this village when I lived here

A

A

Câu A

Ta có:
\(\dfrac{x}{10}=\dfrac{y}{5}\)
\(\Rightarrow\dfrac{x}{20}=\dfrac{y}{10}\)  \(\left(1\right)\)
\(\dfrac{y}{2}=\dfrac{z}{3}\)
\(\Rightarrow\dfrac{y}{10}=\dfrac{z}{15}\)  \(\left(2\right)\)
Từ \(\left(1\right)\) và \(\left(2\right)\)
\(\Rightarrow\dfrac{x}{20}=\dfrac{y}{10}=\dfrac{z}{15}\)
Lại có:
\(\dfrac{z}{15}=\dfrac{4z}{60}\)
Áp dụng tính chất của dãy tỉ số bằng nhau,ta có:
\(\dfrac{x}{20}=\dfrac{y}{10}=\dfrac{4z}{60}=\dfrac{x+4z}{20+60}=\dfrac{240}{80}=3\)
\(\Rightarrow x=3\cdot20=60\)
     \(y=3\cdot10=30\)
     \(z=3\cdot15=45\)

Em chỉ cần đáp án hay cần giải luôn nhỉ?

câu 6: bài học: hãy là chính mình, biết sống hết mình, làm tốt những trách nhiệm, bổn phận của bản thân sẽ được mọi người tôn trọng, yêu quý