16. You should pay more ....................in class.

17. ……………. this invention , we can learn more about the undersea world.

18. People in the countryside have less stress, ................ they usually live longer.

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

19. Vietnamese has some kinds of traditional ................ such as "Cheo" or "Cai luong".

A. music                 B. opera                           C. play                                 D. instrument

20. Johnson is a good guitar player. He plays the guitar very…..........

A. good                       B. bad                         C. well                                    D. fastly

21. It’s difficult to cross this street because there is too much ………..

A. crowd                     B. traffic                                 C. people                                 D. transport

22. Why don’t you visit me? I really look forward to........................you.

 A. see                         B. to see                      C. seeing                                 D. sees

23. I would …….. you about my school and my teachers.

A. tell                          B. telling                                 C. to tell                                  D. tells

24. You'll become healthier if you consume ................ soft drinks.

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

25. A: "................ to France?"  -  B: "Yes, I went to there 2 years ago."

A. Did you ever go   B.Were you ever   C. Have you ever go         D. Have you ever been

Ta có vế phải không âm nên vế trái không âm tức là \(y^2\le25\Leftrightarrow-5\le y\le5\)

Mặt khác thì vế phải chia hết cho 5 nên vế trái chia hết cho 5,suy ra y={-5;0;5}

+)Với y=-5 =>2020(x-2019)²=0=>x=2019

+)Với y=0=> 2020(x-2019)²=25,trường hợp này không tìm được x

+)Với y=-5 thì 2020(x-2019)²=0=>x=2019

Vậy giá trị thỏa mãn của (x;y) là (2019;5);(2019;-5)

sao ko xét th 2,4 VP cũng chia hết cho 2,4 mà

Kẻ Oc//Oa

a c b A O B 3 1 2 3 1

=> \(\widehat{A_1}=\widehat{O_2}\left(slt\right)\Rightarrow\widehat{O_2}=30^{\text{o}}\)

Lại có Oa//Ob ; Oa//Oc

=> Ob//Oc

=> \(\widehat{O_3}=\widehat{B_1}\left(slt\right)\Rightarrow\widehat{O_3}=120^{\text{o}}\)

mà \(\widehat{AOB}=\widehat{O_2}+\widehat{O_3}=30^{\text{o}}+120^{\text{o}}=150^{\text{o}}\)

Trang 2 nhé :

1, Megan arranging flowers

2, Alex and eter detest making pottery

3, My mother hate to climb mountains

4, Alex and Peter hate arranging flowers .

5, My mother adore making pottery

a, \(\frac{x-2}{x+1}=\frac{x-3}{x+2}ĐK:x\ne-1;-2\)

\(\Leftrightarrow x^2-4=\left(x-3\right)\left(x+1\right)\Leftrightarrow x^2-4=x^2+x-3x-3\)

\(\Leftrightarrow2x-1=0\Leftrightarrow x=\frac{1}{2}\)

b, \(\frac{2x+1}{x-3}=\frac{2x-3}{x+1}ĐK:x\ne3;-1\)

\(\Leftrightarrow\left(2x+1\right)\left(x+1\right)=\left(2x-3\right)\left(x-3\right)\)

\(\Leftrightarrow2x^2+2x+x+1=2x^2-6x-3x+9\)

\(\Leftrightarrow2x^2+3x+1-2x^2+9x-9=0\)

\(\Leftrightarrow12x-8=0\Leftrightarrow x=\frac{2}{3}\)