The equation represents height as a function of time.
The bullet was in the air for 75 seconds.
The equation is given as:
The time spent in the air is the time it takes the bullet to land on the ground.
When the bullet is on the ground, the height is:
So, we have:
Factor out t
Split
or
represents when the shot is fired.
So, we solve for t in
Collect like terms
Divide both sides by 16
Hence, the bullet was in the air for 75 seconds
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