Nếu có thể làm thì phiền cậu có thể làm rõ ra 1 tí được không? 

Tìm x:

\(\dfrac{7}{4}-x\times\dfrac{4}{3}=\dfrac{5}{19}\\ x\times\dfrac{4}{3}=\dfrac{7}{4}-\dfrac{5}{19}\\ x\times\dfrac{4}{3}=\dfrac{113}{76}\\ x=\dfrac{113}{76}:\dfrac{4}{3}\\ x=\dfrac{339}{304}.\)

Energy saving
Saving energy doesn’t have to be expensive or time-consuming. But what can you do to save energy? There is (1)______ that you can do to help the process of energy conservation. You can save energy by doing things like making sure that the kettle doesn’t (2)______ more water than that you
need, always washing a full load in the washing machine rather than a half load or turning down
your central heating by 10C – this could cut your (3)______ bill by 10%. Making sure that hot water
taps are not left (4)______ and replace washers if your taps drip. (5)______ work you can turn off (6)______ light and your computer if you are not using them. (7)______ to energy-saving light bulbs – these use around a quarter of electricity, and often last eight times (8)______ than an ordinary bulb. Close your curtains at (9)______ to keep the warm air from escaping through the windows. Switching off (10)______ appliances when they are not in use makes a big contribution to energysaving, too.
1. A. plenty B. lot C. little D. few
2. A. consist B. contain C. compose D. include
3. A. hot B. heat C. heating D. heated
4. A. run B. ran C. running D. flowing
5. A. By B. At C. In D. On
6. A. any B. all C. those D. no
7. A. Change B. Consume C. Buy D. Sell
8. A. higher B. shorter C. less D. more
9. A. morning B. evening C. dusk D. afternoon
10. A. electricity B. electronic C. electric D. electrical

Provide the correct verbs in the form of “will” or “be going to” to fill in the blanks:

1. isn't going to join

2. am going to visit

3. will take

4. won't work

5. will take

6. will win

7. will have

8. are going to be.

1. exciting => excited

2. when => since

3. now => then

4. he now => he does

5. was sent => sent.

2 tạ = ..... yến

Vì tạ cách yến là 1 đơn vị nên ta lấy 2 tạ nhân cho 10 

=> 2 tạ = 20 yến

Vậy: 2 tạ = 20 yến

20 yến = ....... tạ 

Vì yến cách tạ là 1 đơn vị nên ta lấy 20 yến chia cho 10

=> 20 yến = 2 tạ

Vậy: 20 yến = 2 tạ

5 tấn 5 kg = .... kg

Đổi: 5 tấn = ..... kg

Vì tấn cách ki-lô-gam là 3 đơn vị nên ta lấy 5 tấn nhân cho 1000

=> 5 tấn = 5000 kg

=> 5000 kg + 5 kg = 5005 kg

Vậy: 5 tấn 5 kg = 5005 kg

b) 3 giờ = ..... phút

Vì 1 giờ có 60 phút nên ta lấy 3 giờ nhân cho 60

=> 3 giờ = 180 phút

Vậy: 3 giờ = 180 phút

180 phút = .... giờ

Vì 1 giờ có 60 phút nên ta lấy 180 phút chia cho 60

=> 180 phút = 3 giờ

Vậy: 180 phút = 3 giờ.

wise.

b) `7/3` . `2/7` - `2/7` . `10/3` - `2/7`

= `2/7` . (`7/3` - `10/3`) - `2/7`

= `2/7` . -1 - `2/7`

= `-2/7` - `2/7`

= `-4/7`.

a, 216 : x - 117 : x + 18 : x = 9

99 : x + 18 : x = 9

117 : x = 9

x = 117 : 9

x = 13

b, 256 \(\times\) x - 215 \(\times\) x = 29643

41 \(\times\) x = 29643

x = 29643 : 41

x = 723.

$\dfrac{25}{8}$ : x = $\dfrac{5}{16}$

x = $\dfrac{25}{8}$ : $\dfrac{5}{16}$

x = 10

x + $\dfrac{7}{15}$ = $\dfrac{6}{5}$

x = $\dfrac{6}{5}$ - $\dfrac{7}{15}$

x = $\dfrac{11}{15}$

x  : $\dfrac{28}{49}$ = $\dfrac{2}{7}$

x = $\dfrac{2}{7}$ \(\times\) $\dfrac{28}{49}$

x = $\dfrac{8}{49}$.