Answer:
1.one solution is the answer
Step-by-step explanation:
That would be a variable, x being one of the most commonly used variables to represent unknown numbers.
Answer:
7 seconds
Step-by-step explanation:
Distance of the coin above the water is modeled by the equation

where
is time taken to cover the distance
Now equating with zero.

So, time taken by the coin to hit the water is 7 seconds.