Answer:
6.5 seconds
Step-by-step explanation:
Keep in mind that when
, this is the same height for both when the model rocket takes off and lands, so when the rocket lands, time is positive. Thus:

So, the amount of seconds that the model rocket stayed above the ground since it left the platform is 6.5 seconds
Answer:
decrease, increase
Step-by-step explanation:
Answer:
No
Step-by-step explanation:
Neither 4 or 7 is a solution to both equations