Answer:
It takes 3 seconds over the interval [0,3]
Step-by-step explanation:
To find when the roller coaster reaches the ground, find when d=0.

To solve divide each term by 16 and factor:

Solve for t by setting each factor to 0.
t-3=0 so t=3
t+3=0 so t=-3
This means the car is in the air from 0 to 3 second.
Answer:
B
Step-by-step explanation:
25% of 800 is 200, so 800-200 is 600
Answer:
D
Step-by-step explanation:
The formula is y = mx+b where m is the slope and b is the y intercept.
y = 0x + b
7 = (-6)0 + b
7 = 0 + b
b = 7
y = +7
I believe it's a rational number, since it's an integer.