\(2x=3y=5z=>\frac{x}{\frac{1}{2}}=\frac{y}{\frac{1}{3}}=\frac{z}{\frac{1}{5}}\) và x-y+z=-33

Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:

  \(\frac{x}{\frac{1}{2}}=\frac{y}{\frac{1}{3}}=\frac{z}{\frac{1}{5}}=\frac{x-y+z}{\frac{1}{2}-\frac{1}{3}+\frac{1}{5}}=\frac{-33}{\frac{11}{30}}=-90\)  

Ta có: \(\frac{x}{\frac{1}{2}}=-90=>x=\frac{1}{2}.\left(-90\right)=-45\)  

            \(\frac{y}{\frac{1}{3}}=-90=>y=\frac{1}{3}.\left(-90\right)=-30\)  

            \(\frac{z}{\frac{1}{5}}=-90=>z=-90.\frac{1}{5}=-18\)  

Vậy x=-45, y=-30, z= -18

Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:

  \(\frac{x}{2}=\frac{y}{-5}=\frac{y-x}{-5-2}=\frac{-14}{-7}=-2\)

Ta có: \(\frac{x}{2}=-2=>x=2.\left(-2\right)=-4\)  

            \(\frac{y}{-5}=-2=>y=\left(-5\right).\left(-2\right)=10\)  

  Vậy x=-4, y=10 

1. They are going to have a final exam at the end of May.

2. I usually go to school at 6.30 morning.

3. I will phone you on Saturday, at about 11 o'clock.

4. We went to Nha Trang last summer.

5. I saw Hoa and Lan at the party yesterday.

6. We enjoyed the time very much at the party last night.

7. I bought a new bicycle last week.

8. They are showing a new film at ABC Cinema.

9. Nam used to live in a farm when he was a small boy.

10. My grandmother used to do all housework by herself.

1. He can play foofball better than last year . ( good )

2. They can speak English more fluent. than last year . ( fluent )

3. Paul can do his homework more careful than last year . ( careful)

VII.

1. B. born

2. C. arrived

3. B. ways

4. B. led

5. C. message

VIII.

1. D. replying late

2. B. Lan Anh learns maths well.

3. B. A new CD