B

Chọn B

Đáp án B

Lỗi r

8 How much do these apples cost?

9 THis is a blue car

11 Are there 40 classrooms in Phong's school?

13 How wide if the Great wall

5) BPT \(\Leftrightarrow\dfrac{30x-45}{60}-\dfrac{20x+20}{60}>\dfrac{30}{60}-\dfrac{36-12x}{60}\)

\(\Leftrightarrow10x-65>12x-6\) \(\Leftrightarrow-2x>59\) \(\Leftrightarrow x< -\dfrac{59}{2}\)

  Vậy ...

7) ĐK: \(x\ne-3\)

BPT \(\Leftrightarrow\dfrac{x+1}{x+3}-1>0\) \(\Leftrightarrow\dfrac{x+1}{x+3}-\dfrac{x+3}{x+3}>0\) \(\Leftrightarrow\dfrac{-2}{x+3}>0\)

\(\Rightarrow x+3< 0\) \(\Leftrightarrow x< -3\)  

  Vậy ...

9) Sửa đề: \(\dfrac{x^2+2x+2}{x^2+3}\ge1\)

\(\Leftrightarrow\dfrac{x^2+2x+2}{x^2+3}-1\ge0\) \(\Leftrightarrow\dfrac{x^2+2x+2}{x^2+3}-\dfrac{x^2+3}{x^2+3}\ge0\) \(\Leftrightarrow\dfrac{2x-1}{x^2+3}\ge0\)

\(\Rightarrow2x-1\ge0\) \(\Leftrightarrow x\ge\dfrac{1}{2}\)

  Vậy ...

11) BPT \(\Leftrightarrow3x-2\le0\) \(\Leftrightarrow x\le\dfrac{2}{3}\)

  Vậy ...

10) Ta có: \(\dfrac{2x+1}{x^2+2}\ge1\)

\(\Leftrightarrow\dfrac{2x+1-x^2-2}{x^2+2}\ge0\)

\(\Leftrightarrow-x^2+2x-1\ge0\)

\(\Leftrightarrow x^2-2x+1\le0\)

\(\Leftrightarrow x=1\)

12) Ta có: \(\left(x-2\right)\left(x+1\right)\ge0\)

\(\Leftrightarrow\left[{}\begin{matrix}\left(x-2\right)\left(x+1\right)>0\\\left(x-2\right)\left(x+1\right)=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\left[{}\begin{matrix}x-2>0\\x+1< 0\end{matrix}\right.\\\left[{}\begin{matrix}x-2=0\\x+1=0\end{matrix}\right.\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}\left[{}\begin{matrix}x>2\\x< -1\end{matrix}\right.\\\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x\ge2\\x\le-1\end{matrix}\right.\)

1 send - will receive 

2 do - will improve

3 find - will give

4 will go - has

5 will go- gets

6 doesn't phone - will leave

7 don't study - won't pass

8 rains - won't have to

9 won't be able - watch

10 can't move - isn't

11 study - will pass

a computer is used to do that job nowadays

He will be seen off at the airport by all his friends 

Beer used to be drunk for breakfast in England years ago

Tea can not made with cold water.

the floor was being cleaned when i arrived

Should Julia be helped with the sewing ?

⇒5-2x=-5                                                                                                                                      2x=5+5                                                                                                               2x=10 ⇒x=10:2=5

d) 5 - 2x = -17 + 12

    5 - 2x = -5

         2x = 5 - (-5)

         2x = 10

           x = 10 : 2

           x = 5

vậy x =5