The image contains a mathematical problem that seems to involve vector expressions. The text reads (translating the mathematical content):

1. Show that:
   • $a = 3\mathbf{i} - 2\mathbf{j} + \mathbf{k}$
   • $b = \mathbf{i} - 3\mathbf{j} + 5\mathbf{k}$
   • $c = 2\mathbf{i} + \mathbf{j} - 4\mathbf{k}$

The problem likely asks for proving a relationship between these vectors, such as their linear independence, collinearity, or calculating the result of a specific operation (e.g., dot product or cross product).

If you could specify the question further, I can help you solve it in detail!

Would you like a step-by-step explanation of this problem?

Here are five questions that might follow from this topic:

1. How do you determine if three vectors are linearly independent?
2. What is the result of the cross product between two of these vectors?
3. How do you calculate the angle between two vectors?
4. What does it mean for three vectors to be coplanar?
5. How can you find the projection of one vector onto another?

Tip: For vector calculations, remember that the cross product is used to find a vector perpendicular to two given vectors, while the dot product is used to find the angle between them or check for orthogonality.