5000, would be your answer.
Given:
The equation for the area of the first option is:

Where x is the side length of the current square park.
To find:
The side length of the current square park.
Solution:
We have,

It can be written as:

Splitting the middle term, we get




We know that the side length of a park cannot be negative. So, the only possible value of x is 320.
Therefore, the most direct method to solve the given equation is splitting the middle term and the side length of the current square park is 320 meters.
Given:
The graph of a proportional relationship.
To find:
The constant of proportionality, the value of y when x is 24 and the value of x when y is 108.
Solution:
If y is directly proportional to x, then

...(i)
Where, k is the constant of proportionality.
The graph of proportional relationship passes through the point (5,15).
Substituting x=5 and y=15 in (i), we get



Therefore, the constant of proportionality is 3.
Substituting k=3 in (i) to get the equation of the proportional relationship.
...(ii)
Substituting x=24 in (ii), we get
Therefore, the value of y is 72 when x is 24.
Substituting y=108 in (ii), we get
Therefore, the value of x is 36 when y is 108.
Answer:
The data can be modeled using linear equatins, because there's the same amount of population for fish A (+20 per year) and fish B (+30 per year) every year.