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:

Answer:
(5√2) / 2
Step-by-step explanation:
Multiply
(5 / √2) * (√2 / √2) = (5√2) / 2
Answer:
He invested approximately $2,215
Step-by-step explanation:
Mr Y invested $2000 in two accounts.
One pays 7%, and the other pays 5%.
At the end of one year, Mr Y earned $155 in interest. We want to know how much Mr Y invested in the account paying 7%.
Let the amount he invested be X, then
7% of X = 155
(7/100)X = 155
0.07X = 155
X = 155/0.07
= 2,215
He invested approximately $2,215
Answer:
(-2,-4 )
Step-by-step explanation:
-8m-10-2= -8m-12 9m+1 =9m+1