Để \(B\backslash A=\varnothing\) thì \(B\subset A\) hay \(\left\{{}\begin{matrix}m\ge1\\m+1\le5\end{matrix}\right.\Leftrightarrow1\le m\le4\)

Thực hiện theo các bước:

Bước 1: Lấy x1, x2∈(a, b) với x1 ≠ x2 ta thiết lập tỉ số: A =f( x 1) −f( x 2).x1-x2

Bước 2: Khi đó:

Nếu A > 0 với mọi x1, x2∈(a, b) và x1 ≠ x2 thì hàm số đồng biến trên (a, b).

Nếu A < 0 với mọi x1, x2∈(a, b) và x1 ≠ x2 thì hàm số nghịch biến trên (a, b).

câu1: 

- The old tile roofs covered with moss, the streets filled with the red color of lanterns, the intricately carved diaphragms, all bring us back to a world of a few hundred years ago. That is just a simple part of Hoi An ancient town, but it is enough to make people fall in love and forget the way.

câu2: 

- Tourists can visit ancient antiques, they can also enjoy authentic dishes at the anvaf festival, and play card games organized by local people.

câu3:

-  In the evening they can participate in the festival of releasing lanterns and making wishes, and rent boats nearby for beautiful photo steps.

Hoi An villages are famous for their beautiful scenery . They are also

well-known for the coconut palms near Thu Bon River and traditional crafts such as colourful paper lanterns.

Here in Hoi An villages, you can spend time to go to cycling, sailing boat and gardening on the local farms. 

We offer an ecotour to Hoi An villages, and tourists are encouraged to use eco-friendly transport such as bicycles to avoid polluting the environment. You can also buy local products and beautiful crafts to help local businesses!

Call us at 0929292929 and book your tour today!

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