To find the length of BE in the given diagram, let's analyze it step-by-step.

We know:

• BE is a segment marked with the expression 5f - 17.
• AE is marked as 21 - 5.
• ED is marked as f + 2.

The segments appear to be parts of a trapezoid or triangle, but without further information on the conditions (e.g., whether triangles are similar or other constraints), we can't definitively solve for f unless there's an additional relationship.

However, if the segments are equal or based on proportionality, setting the expressions equal may help:

1. Is there any additional condition specifying equality or similarity between segments?
2. If BE must be equal to another segment, we can solve for f.

If more details are provided, I can proceed with solving the equation.

Would you like further clarification, or do you have more conditions related to the diagram?

Related Questions:

1. What is the significance of the expressions in terms of solving for BE?
2. Are there any triangle similarity or congruence properties applicable here?
3. What other geometric relationships exist in the diagram?
4. Could you provide constraints for solving for f?
5. Are BE and ED parts of a proportional relationship?

Tip: When solving problems with variables and segments, look for clues indicating segment equality or proportionality to set up equations.