c

kiến trúc sư

Lời giải:

$2x+3y\vdots 17$

$\Rightarrow 2x+3y+17y\vdots 17$

$\Rightarrow 2x+20y\vdots 17$

$\Rightarrow 2(x+10y)\vdots 17$

$\Rightarrow x+10y\vdots 17$

$\Rightarrow 9x+90y\vdots 17$

$\Rightarrow 9x+90y-17y.5\vdots 17$

$\Rightarrow 9x+5y\vdots 17$ (đpcm)

các PS chứ sao có mỗi 1 PS vậy bạn

Câu 1:

a. $132-468-(-215)=132-468+215=(132+215)-468$

$=347-468=-121$

b.

$(144-97)-156=47-156=-109$

c.

$(-145)-(18-145)=-145-18+145=(-145+145)-18=0-18=-18$

d.

$115+(-15+27)=115-15+27=100+27=127$

e.

$(24+614)-(386-76)=638-310=328$

Câu 2:

a.

$(-105)+x=-217$

$x-105=-217$

$x=-217+105=-112$

b.

$x-67=-23$

$x=-23+67=44$

c.

$4(3-x)=28$

$3-x=28:4=7$

$x=3-7=-4$

d.

$5[x+(-81)]=400$

$x-81=400:5=80$

$x=80+81=161$

e.

$140:(x+108)=7$

$x+108=140:7=20$

$x=20-108=-88$

f.

$-27+(-x)=-104$

$-28-x=-104$
$x=-28-(-104)=-28+104=76$

12,9 kg = \(12,9:100\) tạ = 0,129 tạ 

12,9 kg = 0,129 tạ

486 cm = 4,86 m

4,86m

2\(xy\) + 6 + \(x\) + 3  = 2024

2\(xy\) + \(x\) + 9 = 2024

2\(xy\) + \(x\)  = 2024 - 9

2\(xy\) + \(x\) = 2015

\(x\).(2y + 1) = 2015

\(x\)             = 2015 : (2y + 1)

\(x\in\) Z ⇒ 2y + 1 \(\in\) Ư(2015) = { 1; 5; 13; 65; 31;155; 403;2015}

      Lập bảng ta có:

Bạn nên chia nhỏ nhóm 5, 6 câu 1 lần nhé

V. Tìm lỗi sai trong câu và sửa lại cho đúng với thì hiện tại tiếp diễn.
1. We are listen=> listening  to music in the car right now.
2. They not => are not studying for the exam at the moment.
3. He is playing volleyball with his friends in the park.
4. Is => are you watching TV now.
5. The students are attend=> attending the class today.
6. Are he play=> is he playing video games at the moment?
7. He read=> is reading  a book in his room this evening.
8. She not => doesn't listen to the teacher in the classroom.
9. My aunt have => has been buying some fruits at the flea market.
10. I did not drinking=> drink beer; it's only tea.
11. All of Andy's friends having => are having fun at the party right now.
12. The children play => are playing football in the back yard at the moment.
13. Look! Those people are fight => fighting with each other.
14. Look! Someone is jump => jumping from the bridge.
15. My English speaking skill improving=> has improved  thanks to Elsa Speak.
16. My mother is busy today. She is cook=> cooking dinner.
17. What kind of clothes are children wear => wearing nowadays?
18. They are try => tryingto pass the examination.