Answer:
4
Step-by-step explanation:
Step-by-step explanation:

Answer:
A. 3s
Step-by-step explanation:
The height of the object after t seconds is given by:

When will the object hit the ground?
It hits the ground after t seconds, and t is found when
. So







3 seconds, so the correct answer is given by option a.
1. plug in the numbers for the variables, like this: 9(-5)+18(-1)
2. solve
Hopefully this helps! Let me know if you need more explanation.
Because u might need it in the real world.