Answer:

Step-by-step explanation:
The fish population after t years can be modeled by the following equation:

In which F(0) is the initial population and r is the constant rate of decay.
Year one the fish population was 18000
This means that 
In year three the fish population was 8000 fish.
Two years later, so 






So

Answer:
Your answer is -6.
Step-by-step explanation:
Simplify 2(2x+3) to get 4x+6
Then simplify -6(x+9) to get -6x-54
Now you have 4x+6=-6x-54
Move all of the coefficients to one side:
10x+6=-54
Move all of the constants to the other side:
10x=-60
Divide each side by 10:
10/10x=-60/10
To get your answer of -6.
4^2 = 16
16 x 2 = 32
32, Hope this helps!
The diameter of the circular foundation would be 18.8 feet, and the circumference would be 59.1 feet.