This would be great the faster we can get it done.

option D

0 < t < 3

Step-by-step explanation:

Given in the question the equation

d = 144 - 16t²

where d is the distance

           t is the time

Since, it is a descent, d should be decreasing until it reaches zero

by plugging d = 0 in the equation

0 = 144 - 16t²

-144 = -16t²

144/16 = t²

t² = 9

take square root on both sides

√t² = √9

t = ±3

since time can't be negative so we will reject -3

t = 3

This means that at 3 seconds the roller coaster was at ground but before that it was in the air

so when t < 3 Greg's car was moving in the air.

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.

if a = 1,   and b = 2, then the answer is 47.99999999. if you round that to the nearest whole number, the answer is 48.