Answer:
Step-by-step explanation:
We have the following variables:
y: hours of sleep
x: age
Each day, a young person should sleep 9 hours
This means that y is 9 added to something
plus 1 4 hour for each year that the person is under 18 years of age.
For each year the person is under 18 years of age, she should sleep 1/4 = 0.25h on top of the 9 hours.
So the equation relating hours of sleep y and age x is: