Well, in order to get that you had to do distributive property, distributive property is when you get the outside number next to the parenthesis and multiply it by the numbers or variable inside the parenthesis one by one. So if she was trying to explain how you got the answer you got then you would say you used the distributive property. Now the (-4x)2 would look like (-4x)(-4x) nad the (9)2 will look like (9)(9) that is why it results in 16x2+81. When you square something it means that you multiply the first number or variable or both times the same. That is why you got that answer. Now I am going to make clear that you r(-4x) changed from a negative to a postive because when you multiply a negative times a negative(or divide also) it results in a positve.
Hope I explained it enough
2 times as much.
(In the cereal aisle at Costco they always have 2 boxes a pack)
The third one is the answer
If inspection department wants to estimate the mean amount with 95% confidence level with standard deviation 0.05 then it needed a sample size of 97.
Given 95% confidence level, standard deviation=0.05.
We know that margin of error is the range of values below and above the sample statistic in a confidence interval.
We assume that the values follow normal distribution. Normal distribution is a probability that is symmetric about the mean showing the data near the mean are more frequent in occurence than data far from mean.
We know that margin of error for a confidence interval is given by:
Me=
α=1-0.95=0.05
α/2=0.025
z with α/2=1.96 (using normal distribution table)
Solving for n using formula of margin of error.

n=
=96.4
By rounding off we will get 97.
Hence the sample size required will be 97.
Learn more about standard deviation at brainly.com/question/475676
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The given question is incomplete and the full question is as under:
If the inspection division of a county weights and measures department wants to estimate the mean amount of soft drink fill in 2 liters bottles to within (0.01 liter with 95% confidence and also assumes that standard deviation is 0.05 liter. What is the sample size needed?
There is no figure.
but you can use A^2 + B^2 = C^2
C is your hypotenuse.
so if you have the other two lengths if you square them and add them you'll have C squared. So you'll have to find the square root of that number to actually find the length.