SOLUTION.
The basketball court is rectangle. To solve this question, we need to know the formula for the perimeter of a rectangle
The perimeter of a rectangle is given by

The expression giving from the question, we have

Substitute into the formula, we have

factorize the common factor on the lefth-hand side, we have

Subtract m² from both sides of the equation, we obtain

Hence
The expression for the length is 17m²+ m - 5
Answer: L= 17m²+ m - 5