The first option is your answer.
Sigma notation is just a fancy way to shorten a sum of a series of numbers using a set equation. The "n =" tells you where to start in the sequence and the top number tells you where to stop.
Answer:
(-1,-2)
Step-by-step explanation:
Let's bring back to memory vertex formula for parabolas.

Where (h,k) is the vertex.
In 
The vertex is (-1,-2)
Answer:
Step-by-step explanation:the half of 32 is 16 so 16 times 2 =-=
The answer you are looking for is 60 yards!
You can use the formula x*y=z
Making 40*y=2400
Do 2400/40= 60
40*60=2400
Making 60 your length of the playground!
I hope this helps!