19,My father used to smoke

20,The cake is cleverly cut by her 

21,Ba offered Mai to dance 

22,My father told us that he was very happy then

1. what he often did on Sunday mornings.

2. I must finish the report by ten o'clock

3. was hot so we turned on the air conditional

4. my favourite band wouldn't leave here tomorrow

5. have you learned English?

6. Tung if he liked dancing.

7. so she got good grades in her exam

8.  he didn't make such terrible mistakes

9. Tom what  he would do after that class.

lỗi r bn

???

1: Ta có: \(3\left(x+5\right)-2\left(4-3x\right)=7\)

\(\Leftrightarrow3x+15-8+6x=7\)

\(\Leftrightarrow9x=14\)

hay \(x=\dfrac{14}{9}\)

2: Ta có: \(x\left(7-2x\right)+2x\left(x-2\right)=15\)

\(\Leftrightarrow7x-2x^2+2x^2-4x=15\)

\(\Leftrightarrow3x=15\)

hay x=5

3: Ta có: \(2x\left(9x-4\right)-9x\left(2x-3\right)=-38\)

\(\Leftrightarrow18x^2-8x-18x^2+27x=-38\)

\(\Leftrightarrow19x=-38\)

hay x=-2

7: Ta có: \(\left(x-5\right)\left(x+5\right)-\left(x-5\right)^2=30\)

\(\Leftrightarrow x^2-5-x^2+10x-25=30\)

\(\Leftrightarrow10x=60\)

hay x=6

8: Ta có: \(\left(x+2\right)\left(x-2\right)+8=\left(x-1\right)^2\)

\(\Leftrightarrow x^2-4+8=x^2-2x+1\)

\(\Leftrightarrow-2x=3\)

hay \(x=-\dfrac{3}{2}\)

1D

2A

D, c

`@` `\text {Ans}`

`\downarrow`

`a)`

`-3x - 3/4 = 6/5`

`=> -3x = 6/5 + 3/4`

`=> -3x = 39/20`

`=> x = 39/20 \div (-3)`

`=> x = -13/20`

Vậy, `x=-13/20`

`b)`

`1/7 - 3/5x = 3/5`

`=> 3/5x = 1/7 - 3/5`

`=>3/5x = -16/35`

`=> x = -16/35 \div 3/5`

`=> x = -16/21`

`c)`

`3/7 - 1/2x = 5/3`

`=> 1/2x = 3/7 - 5/3`

`=> 1/2x = -26/21`

`=> x = -26/21 \div 1/2`

`=> x = -52/21`

Vậy, `x = -52/21`

`d)`

`-2/3x + 2 = 3/4`

`=> -2/3x = 3/4 - 2`

`=> -2/3x = -5/4`

`=> x = -5/4 \div (-2/3)`

`=> x = 15/8`

Vậy, `x=15/8.`

8 It took me 3 hours to do these exercise

9 Many years ago, my village used to be very poor

10 Mary last met him 5 years ago

11 Would you mind giving me a hand

12 There used to be many old buildings in this city

13 When were they married

14 I started learning Japanese 2 years ago

15 Jack used to be a good student

16  My sister used to buy all her clothes in Henry's

17 Braille is reading system for the blind

(2x+1)²+2(2+1)

=4x²+4x+1+4+2

=4x²+4x+7

a: Xét ΔBAE và ΔBDE có

BA=BD

\(\widehat{ABE}=\widehat{DBE}\)

BE chung

Do đó: ΔBAE=ΔBDE

b: Ta có: ΔBAE=ΔBDE

nên \(\widehat{BAE}=\widehat{BDE}=90^0\)

hay ED\(\perp\)BC

c: Xét ΔAKE vuông tại A và ΔDCE vuông tại D có

EA=ED

\(\widehat{AEK}=\widehat{DEC}\)

Do đó: ΔAKE=ΔDCE
Suy ra: EK=EC
hay ΔEKC cân tại E