Answer:
C. 4.2a + 0.8
Step-by-step explanation:
Given:
The two binomials given for addition are:
and 
Now, adding both the binomials, we get:

Distributing the positive sign inside the second binomial, we get:

Now, combining like terms using the commutative property of addition, we get:

Simplifying the above expression, we get:

Therefore, the resulting addition of the given binomials is 
Hence, option C is the correct answer.
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Answer: a. n= 1068
b. n= 164
Step-by-step explanation:
The formula to find the sample size :

, where p=prior population proportion , z* = critical z-value and E = Margin of error.
Here , let p=proportion of computers that use a new operating system.
Given : Confidence level = 95%
i.e. z* = 1.96 [by z-table]
Margin of error : E = 3% =0.03
a. If p is unknown , then we assume p=0.5
Then, 
i.e. n= 1068
b. p=0.96
Then, 
i.e. n= 164.
I think it might be B. but im not sure.
Answer: 45
Step-by-step explanation:180 divided by 4 = 45