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NV
6 tháng 8

\(\left(15-x\right)+2=12\)

\(15-x=12-2\)

\(15-x=10\)

\(x=15-10\)

\(x=5\)

6 tháng 8

(15 - x) + 2 = 12

=> 15 - x = 12 - 2

=> 15 - x = 10

=> x = 15 - 10

=> x = 5 

Vậy: ... 

\(\dfrac{1}{2}:\dfrac{3}{8}-0,25\times\dfrac{8}{5}\)

\(=\dfrac{1}{2}\times\dfrac{8}{3}-\dfrac{1}{4}\times\dfrac{8}{5}\)

\(=\dfrac{4}{3}-\dfrac{2}{5}=\dfrac{20}{15}-\dfrac{6}{15}=\dfrac{14}{15}\)

thank bạn

 

10+(x-5)=10

=>x-5=10-10=0

=>x=0+5=5

23 tháng 6 2023

  a,

S  =     1 -  3 + 32 - 33+...+398 - 399

S  =   30 - 31 + 32 - 33+...+ 398 - 399

xét dãy số: 0; 1; 2; 3;...;99 

Dãy số trên là dãy số cách đều với khoảng cách là: 1 - 0 = 1

Dãy số trên có số số hạng là: (99 - 0): 1 + 1 = 100 (số)

100 : 4 = 25

Vậy ta nhóm 4 số hạng liên tiếp của tổng S thành 1 nhóm thì: 

S = ( 1 - 3 + 32 - 33) +....+( 396 - 397 + 398 - 399)

S = - 20+...+ 396.(1 - 3 + 32 - 33)

S = - 20 +...+ 396.(-20)

S = -20.( 30 + ...+ 396) (đpcm)

b,

  S           = 1 - 3 + 32 - 33+...+ 398 - 399

3S          =      3  - 32 + 33-...-398  + 399 - 3100

3S + S   =    - 3100 + 1

4S        = - 3100 + 1 

 S        = ( -3100 + 1): 4

S        = - ( 3100 - 1) : 4

Vì S là số nguyên nên 3100 - 1 ⋮ 4 ⇒ 3100 : 4 dư 1 (đpcm)

 

1.     What time you (have) _______________________________________________lunch every day? 2.     The plane (fly) ____________________________________________to London every Monday. 3.     My friend often (draw) ______________________________________________  nice posters. 4.     London ______________ (be) a very big country 5.     My father (not/read)____________ the newspaper every morning. 6.     He (go)                    to school every day. 7.     She (come)   ...
Đọc tiếp

1.     What time you (have) _______________________________________________lunch every day?

2.     The plane (fly) ____________________________________________to London every Monday.

3.     My friend often (draw) ______________________________________________  nice posters.

4.     London ______________ (be) a very big country

5.     My father (not/read)____________ the newspaper every morning.

6.     He (go)                    to school every day.

7.     She (come)                       from Germany.

8.     My parents usually (go)                        to work by car.

9.     We (watch)                      TV every night.

10. He (walk)                       to work every day.

11. He (be)                           in Ca Mau.

12. They (be)                          students.

13. She (wash)                          her clothes every Sunday.

14. She (study)                           English every day.

15. He (want)                             to become a teacher.

16. She usually (walk)   to school.

17. What time                 Mary usually (get) up every morning?

18. She (not wash)                   her clothes every weekend. 14 they (be)             teachers?

19.  It (not be) often                 cold in summer.

5
5 tháng 8

1 What time do you have lunch every day?

2 flies

3 draws

4 is

5 doesn't read

6 goes

7 comes

8 go

9 watch

10 walks

11 is

12 are

13 washes

14 studies

15 wants

16 walks

17 does - get

18 doesn't wash

Are they teachers?

19 isn't

6 tháng 8

1.     What time do you (have) _____________have_________________________________lunch every day?

2.     The plane (fly) __________flies__________________________________to London every Monday.

3.     My friend often (draw) _______draws_______________________________________  nice posters.

4.     London _______is_______ (be) a very big country

5.     My father (not/read)_______doesn't read_____ the newspaper every morning.

5 tháng 8

1. modern

2. stairs

3. elevator

4. cary

5. really

6. buttons

7. climb

8. wonderful

9. Could

10. push

#hoctot

 

6 tháng 8

1 modern

2 stairs

3 elevator

4 carry

5 really