1. People speak English over the world. 

English is spoken over the world.

2. Someone stole my bike last night. 

My bike was stolen last night

3. The coffee is so hot that I can't drink it. 

The coffee is too hot for me to drink.

4. My mother has bought a new house in the town center. 

A new house has bought in the town center by my mother. 

5. My father will repair my bike tomorrow. 

My bike will be repaired tomorrow by my father.

Hue Imperial City

1 . She ( not / study ) doesn't study on every Friday.

1.     Nam sometimes (go) goes fishing with his friends.

2.     We seldom (eat) eats before 6.30.

3.     The sun ( set)  sets in the West.

4.     It (be) is often hot in the summer.

5.     She always (cook) cooks in the morning.

6.     My father usually (watch) watches the news at 7.00

7.     What do you (do) do every morning?

8.     She (not drink) doesn't drink coffee. She (drink) drinks water.

9.     We (be) are in grade 8 this year.
10.   Lien’s mother (teach) teaches Math in our school.
11.  Nam sometimes (go) goes fishing with his friends.
12.  We seldom (eat) eats before 6.30.

sgk có nhé bn

\(\frac{x}{y}=\frac{2}{5}\Rightarrow\frac{x}{2}=\frac{y}{5}\)

Áp dụng tính chất của dãy tỉ số bằng nhau ta có:
\(\frac{x}{2}=\frac{y}{5}=\frac{x-y}{2-5}=\frac{15}{-3}=-5\)

\(\Rightarrow\begin{cases}\frac{x}{2}=-5\rightarrow x=\left(-5\right)\cdot2=-10\\\frac{y}{5}=-5\rightarrow y=\left(-5\right)\cdot5=-25\end{cases}\)

đề sai rồi, mk đang làm dở tự nhiên thấy sai xog lại xóa đi 

Rút gọn xong ròi thay vào kt

Bài 3:

a) \(f\left(x\right)=-15x^2+5x^4-4x^2+8x^2-9x^3-x^4+15-7x^3\)

\(f\left(x\right)=\left(5x^4-x^4\right)-\left(9x^3+7x^3\right)-\left(15x^2+4x^2-8x^2\right)+15\)

\(f\left(x\right)=4x^4-16x^3-11x^2+15\)

b) 

\(f\left(x\right)=4x^4-16x^3-11x^2+15\)

\(f\left(1\right)=4\cdot1^4-16\cdot1^3-11\cdot1^2+15\)

\(f\left(1\right)=4\cdot1^4-16\cdot1^3-11\cdot1^2+15\)

\(f\left(1\right)=-8\)

\(f\left(x\right)=4x^4-16x^3-11x^2+15\)

\(f\left(-1\right)=4\cdot\left(-1\right)^4-16\cdot\left(-1\right)^3-11\cdot\left(-1\right)^2+15\)

\(f\left(-1\right)=24\)