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24 tháng 10 2021

\(\frac{a}{b}=\frac{5}{-3}\)   và   \(a-b=16\)

\(\Rightarrow\)\(\frac{a}{b}=\frac{5}{-3}\Leftrightarrow\frac{a}{5}=\frac{b}{-3}\)

Áp dụng tính chất của dãy tỉ số bằng nhau, ta có:

\(\frac{a}{5}=\frac{b}{-3}=\frac{a-b}{5-\left(-3\right)}=\frac{16}{8}=2\)

Do đó:

\(\frac{a}{5}=2\Rightarrow a=5.2=10\)

\(\frac{b}{-3}=2\Rightarrow b=-3.2=-6\)

Vậy: \(a=10;b=-6\)

I. Choose the best answer (A, B, C or D).1.        My father can make beautiful pieces of art                  empty eggshells.A.of                             B. from                        C. in                            D. into2.        Why don’t you take                  a new hobby?A.up                            B....
Đọc tiếp

I. Choose the best answer (A, B, C or D).

1.        My father can make beautiful pieces of art                  empty eggshells.

A.of                             B. from                        C. in                            D. into

2.        Why don’t you take                  a new hobby?

A.up                            B. in                            C. over                        D. after

3.        Collecting cars is a(n)                   hobby. It costs a lot of money.

A.interesting               B. cheap                      C. expensive                D. unusual

4.        Have you ever taken part                volunteer work?

A.    for                         B. to                            C. in                            D.with

5.        We have raised money for people in need                2015.

A.in                             B.at                             C. since                       D. for

6.        She’s got a high                – almost 40°.

A.flu                            B. headache                C. sore throat              D. temperature

7.        Jane is                weight because she eats too much junk food.

A.getting over             B. putting on               C. taking up                D. throwing away

8.        The charity                facilities for disabled people to take part in sport.

A.provides                  B. donates                   C. raises                       D. collects

9.        More people are                   birds today than ever before.

           A. seeing                     B. looking                   C. hearing                    D. watching

10.     Do you enjoy                  board games?

A.play                         B. to play                    C. playing                    D. played

11.     Be careful not to drop it; it’s very                 .

A.    unique                    B. fragile                     C. difficult                   D. unusual

12.     If you want to stay healthy, eat                 vegetables, whole grains, fruit and fish.

A.much                       B. fewer                      C. more                       D. less

13.     Fruit tastes good                  it’s healthy for your body.

A.so                             B. but                          C. or                            D. and

     14. You should know       you eat, so you don’t eat unhealthy foods.

           A. what                        B.who                         C. which                      D. that

     15. She looks very tired. She should work                  or she will get sick.

A. well                        B. less                          C more                        D. enough

1.        She stays in                  by exercising daily and eating well.

A. health                     B. fit                            C. size                         D. shape

     17. My sister has an ................... to sunflowers so I don’t arrange them in the house.

            A. earache                  B.allergy                   C. itchy                           D.backache

18.  Please wake me                _ at 5 and we will leave at 6 in the morning.

            A. up                          B. on                           C. over                        D. in

19.  If you want to                 weight, you should follow a low-fat diet.

A.    lose                       B. gain                         C. put on                    D. take

14

TL

6 C

7 D

8 A

9 B

10 B

11 C

T i k cho mik tiếp mik trả lời nốt cho

24 tháng 10 2021

 1. B

2. A

3. C

4. C

5. C

6. D

7. B

8. A

9. D

10. C

11. C

12. C

13. D

14. A

15. B

16. D

17. B

18. A

19. C

24 tháng 10 2021

bài tập về nhà dễ như vậy sao không tự làm đi

24 tháng 10 2021

\(\left(3-\frac{2}{3}+\frac{4}{3}\right):\left(2\frac{1}{3}-2,5\right)^2\)

\(=\left(\frac{7}{3}+\frac{4}{3}\right):\left(2\frac{1}{3}-2\frac{1}{2}\right)^2\)

\(=\frac{11}{3}:\left(-\frac{1}{6}\right)^2\)

\(=\frac{11}{3}:\frac{1}{36}\)

\(=\frac{11}{3}x\frac{36}{1}\)

\(=\frac{396}{3}\)

\(=132\)

24 tháng 10 2021

(3-2/3+4/3):(2 1/3-2,5)2

= -17/6:121/36

=-36/121

25 tháng 10 2021

undefined

Từ O vẽ Oz // Mx.

Ta có : Oz // Mx 

         = > xMO = MOz (so le trong)

Ta lại có : Oz // Mx 

             Mà Mx // Ny (giả thiết)

     => Oz // Ny (Tiên đề Ơ - clít)

          = > zOn + ONy = 180 (Trong cùng phía)

                 zOn = 180 - ONy = 180 - 110 = 70

 Có : MON = MOz + zON = 20 + 70 = 90

=> MO vuông góc với ON