1. Đọc đoạn văn sau và khoanh tròn câu trả lời đúng:

Mai lives in Ha Noi, but her hometown is Nam Dinh province in the north of Viet Nam. Last weekend, Mai's family went back to their hometown to visit her grandparents. They went to Nam Dinh railway station by train. From there, they went to her grandparents' house by bus. The family were happy to see them. The following day, they went to the seaside, swam in the sea and ate seafood. They came back home late in the evening.

1. Mai's hometown is Ha Noi. a. True b. Flase

2. grandparents live in Nam Dinh province. a. True b. Flase

3. Mai's family went to her hometown last year. a. True b. Flase

4. They went there by coach. a. True b. Flase

5. They were on the beach the following day. a. True b. Flase

Read again and write short answers.

1. Where is Mai's hometown?

=> Mai's hometown is Nam Dinh province.

2. Where is Nam Dinh Province?.

=> It's in the north of Viet Nam.

3. How did Mai's family get to Nam Dinh Railway Station?

=> By train.

4. Where did they go the following day?

=> They went to the seaside.

5. When did they come back home?

=> In the evening

a) 32⁵⁰ = 2²⁵⁰ < 2²⁵⁵ = 8⁸⁵

27⁵¹ = 3¹⁷¹ > 3¹⁷⁰ = 9⁸⁵

Vì 8⁸⁵ < 9⁸⁵ nên 32⁵⁰ < 27⁵¹

b) 31⁹ < 32⁹ = 2⁴⁵

9¹⁶ > 8¹⁶ = 2⁴⁸

Vì 2⁴⁵ < 2⁴⁸ nên 31⁹ < 9¹⁶

c) Chịu :)

32⁵⁰ = 2²⁵⁰ < 2²⁵⁵ = 8⁸⁵

27⁵⁷ = 3¹⁷¹ > 3¹⁷⁰ = 9⁸⁵

Vì 8⁸⁵ < 9⁸⁵ nên 32⁵⁰ < 27⁵⁷

Văn bản nào =.=

Để A đạt GTLN thì \(2x^2+10x-1\) phải đạt GTNN

Ta có: \(2x^2+10x-1\)

= \(2\left(x^2+5x-\dfrac{1}{2}\right)\)

= \(2\left(x^2+5x+\dfrac{25}{4}-\dfrac{27}{4}\right)\)

= \(2\left[\left(x+\dfrac{5}{2}\right)^2-\dfrac{27}{4}\right]\)

= \(2\left(x+\dfrac{5}{2}\right)^2-\dfrac{27}{2}\) \(\ge\) \(-\dfrac{27}{2}\) với mọi x

Min_A = \(\dfrac{2}{\dfrac{-27}{2}}=-\dfrac{4}{27}\) khi và chỉ khi x = \(-\dfrac{5}{2}\)