The subtraction theorem states that for all real numbers,

and

,

.
(To subtract, we can add the inverse.)
Thus, we can have the these two equivalent expressions.
Answer:
To obtain a valid approximation for probabilities about the average daily downtime, either the underlying distribution(of the downtime per day for a computing facility) must be normal, or the sample size must be of 30 or more.
Step-by-step explanation:
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean
and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean
and standard deviation 
In this question:
To obtain a valid approximation for probabilities about the average daily downtime, either the underlying distribution(of the downtime per day for a computing facility) must be normal, or the sample size must be of 30 or more.
Step-by-step explanation:
6x + 120y + 6x2
Final answer
Answer:
The correct answer is option A.120
Step-by-step explanation:
Let's start by analyzing the information they have given us.
We know that the stereo has a list price of $ 150, but at the time of payment, we are told that it has a 20% discount.
Now we must find out what the discount was applied to know the final price of the stereo.
One way to calculate the percentage would be multiplying 150 by 0.20
150.0.20 = 30
The discount applied is $ 30, so now we just have to subtract that amount from the original price:
150-30 = 120
Therefore, the correct answer is option A.