Answer: Yes, the set of real numbers is closed under addition.
Explanation:
Let x and y be two real numbers. Their sum x+y is some other real number. This is what it means when we say the set of real numbers is closed under addition. Taking any two numbers and adding them will get us some other real number.
There is no way to have x+y be nonreal while x,y are both real.
Answer: 10
Step-by-step explanation:
Formula : √(xB−xA)2+(yB-yA)2
= √(−8)2+62
= √64+36
= √100 = 10
Answer: Alice
Step-by-step explanation: Alice won because she started furthest From the starting line.
Answer:
We need a sample size of at least 369.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
The margin of error is:
For this problem, we have that:
90% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
How large of a sample size is required?
We need a sample size of at least n.
n is found when 
. So
Rounding up
We need a sample size of at least 369.
Answer:
Anya is incorrect.
Step-by-step explanation:
=)
The correct answer is x = −1 or x = 7
=)
