They are essentially asking us to solve:

Solving this equation for x tells us that it will take around 80.1 years for the materials in the vault to reduce to 357 pounds.
Interest earned = 194.784
balance = $944.78
Answer: 9
Step-by-step explanation: Basically what f(-2) means is -2 = x. So you put in -2 wherever x appears. This would turn the equation to -3(-2) + 3 which goes to 6+3.
Answer:
t ≥ 10
Step-by-step explanation:
Since the student needs at least 10 hours of driving time, they need greater than or equal to 10 hours to pass.