Cho x^ 2+5y^2 -4xy-6y+9=0 . Tính giá trị của A= 𝑥+𝑦 / x-y 

nêu những sự vật khơi nguồn cảm xúc của nhân vật tôi

 Chứng minh rằng mỗi biểu thức sau luôn dương với mọi giá trị của biến

E= 2x^2+y^2 -2xy -6x+12

 Cho x^2 -y ^2=4z^2 . CMR: (5x-3y+8z)(5x-3y-8z)=(3x-5y)^2

V. Choose the underlined part, A, B, C or D that needs correcting.

1. Having leisure activities are truly important to the elderly.

         A                                   B                            C           D

2. Although she wanted to go to the museum, she decided staying at home.

           A                      B                                               C

3. Parents are concerned that their kids may be spending too many time on screens.

                              A                                                  B             C                      D

4. Collecting coins is exciting, but it can also be relaxed.

            A                  B       B                                          D

5. Cloud watching sound weird, but Hang adores it.

                  A               B                  C                        D

6. For some young people, enjoyment involves sitting in front a computer

           A                                                             B                C            

playing games.

           D

7. His parents are thinking of banning him on using the computer.

                                     A             B              C     D

8. When you game online, be carefully when making friends with strangers.

                         A                          B                     C                    D