The image you uploaded contains a set of math problems written in Vietnamese. Here's a brief breakdown:

• Bài 1 asks about simplifying and evaluating an expression $B$ at a given value of $x$.
• Bài 2 involves solving a practical word problem about a group of people completing a task.
• Bài 3 involves geometry and algebra questions regarding a parabola and a line, with a specific focus on calculating equations and distances.

Would you like help with solving any of these problems, or do you need more details on a specific part? Let me know how you'd like to proceed!

Here are 5 related questions:

1. How can I simplify the expression for $B$ in Bài 1?
2. What is the method for solving a word problem involving work completion rates in Bài 2?
3. Can you help me derive the equation of the line in Bài 3?
4. How do I calculate the distance between two points A and B in Bài 3?
5. What is the process for proving the triangle OAB is right-angled in Bài 3?

Tip: Always break word problems into smaller parts to identify key information for forming equations or applying mathematical operations.