1 Bộ may hết:

    75,9:30=2,53(m)

50 bộ may hết:

  2,53 x 50=126,5(m)

             Đ/s:

Đề dài quá. Bạn nên tách lẻ post từng bài từng post để mọi người hỗ trợ tốt hơn nhé.

7,5

7,1 ; 7,2 ; 7,3 ; 7,4;.......(rất nhiều số thập phân)

là bí mật

là bí mật

Hello my name is thao anh .today i will talk about my favourite fesstival.its called tet.do you know?tet is the biggest traditional festival in vietnam.before tet people often decorate their house,buy fruit and flowers.before tet,i often help my family to clean the house,ưater the plants,so tired!during tet,people often go outside to watch lion daces.my family usually eat traditional food like chicken and noodles.i can get lucky money during tet.my realative sometimes give me some lucky money.i often spend it on comics and books.i really like tet becauss i dont need to go to school 

Hello my name is thao anh .today i will talk about my favourite fesstival.its called tet.do you know?tet is the biggest traditional festival in vietnam.before tet people often decorate their house,buy fruit and flowers.before tet,i often help my family to clean the house,ưater the plants,so tired!during tet,people often go outside to watch lion daces.my family usually eat traditional food like chicken and noodles.i can get lucky money during tet.my realative sometimes give me some lucky money.i often spend it on comics and books.i really like tet becauss i dont need to go to school 

Lời giải:
Theo đề thì $x=ƯC(245,294)$

$\Rightarrow ƯCLN(245,294)\vdots x$

$\Rightarrow 49\vdots x$

$\Rightarrow x\in \left\{1; 7; 49\right\}$

Mà $25< x\leq 51$ nên $x=49$

1 + (-5) + 11 + (-15) + 21 + (-25)

= [1 + (-5)] + [11 + (-15)] + [21 + (-25)

= -4 + (-4) + (-4)

= -4 x 3

= -12

1. B

2. B

3. A

4. C

5. B

6. C

7. B

8. B

9. C

10. A