The image you uploaded appears to be a geometry problem in Vietnamese. Let me break down and translate the parts of the problem:

1. Given:

   • A right triangle ABC with $AB < AC$, right-angled at A.
   • The height $AH$ is drawn from vertex A perpendicular to the side BC, meeting BC at point H.
   • A circle with center $O$ intersects side $BC$ at point E.

2. Tasks:

   • a) Prove that the line $CA$ and the line $CE$ are tangent to the circle at point E.
   • b) Prove that the line $AK$ is perpendicular to $BC$, where $K$ is the point of intersection of the line $AK$ with side $BC$ at point Q.
   • c) Prove that $F$ is the intersection of the lines $EQ$ and $BK$, and demonstrate that triangle $\Delta KEF$ is congruent to triangle $\Delta QEF$.

This looks like a rich geometric proof that involves proving tangency, perpendicularity, and congruency of triangles.

Would you like help with any specific part of the problem or a step-by-step solution for each part? Let me know what you'd like to explore first.

Here are some related questions for further understanding:

1. How do you prove that a line is tangent to a circle?
2. What is the condition for two triangles to be congruent?
3. How can you use the concept of perpendicularity in geometry?
4. What properties does a right triangle with an altitude have?
5. How can you demonstrate the intersection of two lines in geometry?

Tip: To prove tangency, you can often use the fact that the radius of the circle at the point of tangency is perpendicular to the tangent line.