Tìm GTLN của B=-x^2-6x+20 C=-2x^2+5x+21

Câu IV. Viết dạng đúng của động từ trong ngoặc trong các câu sau. (1,0 điểm) 1. Would you mind (1. tell)………. me where I can go to post the letter ? 2. When my mother came home from work, I (2. cook)………. dinner. 3. Are you used to (3. watch)…….. television after dinner? 4. This horse can (4. ride) …………….by the boy.

Câu 1 : a) Tìm điều kiện `E = \sqrt{5 - x} + x` b) Rút gọn `F = \sqrt{9a ²b ² + 36a ² - 36a ²b}` với a > 0 ; b < 2

so sánh x=2020a và y=2020+a (với x,y là tham số)

Câu III. Tìm một lỗi sai trong bốn phần gạch chân A, B, C hoặc D trong các câu sau đây. (1,0 điểm) 1. It took Peter three hours opening the doors. A B C D 2. Nam is one of my friends whom tried hard to succeed in his studying at school. A B C D 3. Despite I didn’t like the sweater, I decided to buy it. A B C D 4. If you work hard, you would get good marks. A B C D

a) S = 2+4+6+8+....+1998 b) S = 1+3+5+7+...+1999

1. People throw rubbish on the street. The street does not look attractive. If people did…………………………… . 2. There are so many billboards in our city. People can not enjoy the view. Were there………………………………… 3. There is so much light in the city at night. We can not see the stars clearly. If there…………………………………… 4. We turn on the heater all the time. We have to pay three million dong for electricity a month. If we……………………………………… 5. The karaoke bar makes so much noise almost every night. The residents complain to its owner. If…………………………………… 6. She has a headache after work every day. She works in a noisy office. Were she…………………………………

Cân bằng các phản ứng hoá học sau 1. FeO + O2 " Fe2O3 2. FexOy + O2 " Fe2O3 3. Al + HCl " AlCl3 + H2 4. Al2O3 + H2SO4 - - ® Al2(SO4)3 + H2O 5. Al(OH)3 + HNO3 " Al(NO3)3 + H2O 6. Al + H2SO4 " Al2(SO4)3 + H2 7. C4H10 + O2 " CO2 + H2O 8. KMnO4 " K2MnO4 + MnO2 + O2 9. Cu(NO3)2 " CuO + NO2 + O2 10. M2Ox + HNO3 " M(NO3)x + H2

4. Cho `a^3b^3+b^3c^3+c^3a^3=3a^2b^2c^2`. Tính `P=(1+a/b)(1+b/c)(1+c/a)`

Trong hình vuông ABCD lấy điểm O sao cho OA : OB : OC = 1 : 2 : 3. Tính số đo góc AOB.