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
Read more about height and time at:
brainly.com/question/2261757
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Answer:
Step-by-step explanation:
If you have written g(x) correctly then g(-5) = 3.40 - 8 = -4.6
If you meant to write g(x) = 3.40x - 8, then g(-5) = -25