Answer:

Step-by-step explanation:
we have the expression:

To factor this expression we need to indentify the components that are common in both terms.
At first glance there is nothing in common, but we can notice that 30 and 70 are multiples of 10, that is:

so we can substitute this into the expression:

and now that we have the common term (the number 10) we can factorize it, that is, take out the common term and include a parentheses:

For large sample confidence intervals about the mean you have:
xBar ± z * sx / sqrt(n)
where xBar is the sample mean z is the zscore for having α% of the data in the tails, i.e., P( |Z| > z) = α sx is the sample standard deviation n is the sample size
We need only to concern ourselves with the error term of the CI, In order to find the sample size needed for a confidence interval of a given size.
z * sx / sqrt(n) = width.
so the z-score for the confidence interval of .98 is the value of z such that 0.01 is in each tail of the distribution. z = 2.326348
The equation we need to solve is:
z * sx / sqrt(n) = width
n = (z * sx / width) ^ 2.
n = ( 2.326348 * 6 / 3 ) ^ 2
n = 21.64758
Since n must be integer valued we need to take the ceiling of this solution.
n = 22
Answer:
b
Step-by-step explanation:
plz mark brainliest
Answer:
60 miles per hour southeast.
Step-by-step explanation:
We are told that the car is moving southeasternly, so that answers the question right off the bat. The car is moving 120 miles per 2 hours. We need to know how much it moves in one hour though, so we must divide hours and miles by 2. We ger 60 miles per hour.
Answer:
No. Remember, a right angle must have a 90 degree angle. We can find the lengths with the Pythagorean Theorem.
Step-by-step explanation:
Given the length 7, 10, and 12, we can assume that 12 is the hypotenuse (it is the longest length).
- we can use 7 and 10 interchangeably.
Fill in the equation, 
where c = 12, and a or b = 7 or 10.
To indicate if the given lengths would form a right angle, we can only input 7 or 10, not both.
Therefore,
or 
==> 49 + b^2 = 144 ==> <u>b= </u>
<u> ==> </u><u>9.746</u>
b= 9.7, not 10.
==> 100 + b^2 = 144 ==> <u>b = </u>
<u> ==> </u><u>6.633 </u>
b= 6.6, not 7.
Therefore, the lengths 7, 10, and 12, does NOT make a right triangle.
Hope this helps!