1/5(100x - 105y + 70) = 20x -21y + 14
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
Answer:
What are the following?
Step-by-step explanation:
Answer:
5 pounds.
Step-by-step explanation:
2 1/2 = 2.5
2.5 x 2 = 5