To represent this situation as an algebraic expression, we need to account for the perimeter of the rectangular field, since the fencing will cover all four sides of the field.

The formula for the perimeter of a rectangle is:
$\text{Perimeter} = 2(\text{Length} + \text{Width})$

Here, the width of the field is $50 \, \text{meters}$, and the length is $x \, \text{meters}$. The total amount of fencing required is $260 \, \text{meters}$. Substituting these into the formula gives:
$2(x + 50) = 260$

Final Expression:

$2(x + 50) = 260$

This equation represents the relationship between the dimensions of the field and the amount of fencing needed.

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Would you like me to:

1. Solve for $x$?
2. Explain how to isolate $x$ in detail?
3. Provide a graph of the equation?
4. Convert this into a word problem explanation for a younger audience?
5. Discuss other scenarios where this equation might apply?

Tip: When solving for a variable, always simplify step-by-step to avoid errors.