X+3y = 2
1 answer:
Answer:
The value of "x" is 5.
Step-by-step explanation:
In order to solve this system of equations, we first have to take the first equation and use it to represent "y" in terms of "x". We do that in the following way...
Now, we need to take the second equation and substitute "y" for the equivalent value in terms of "x". After doing this we will get the following equation, which we can solve to get the value of "x".
Therefore, the value of "x" is 5.
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Hi there! :)
Find the central angle using a ratio in regards to angle and circumference.
The radius is 27 units, so use the following equation to calculate circumference:
C = 2rπ
Therefore:
C = 2(27)π = 54π
Since we have the total circumference, we can write the following proportion:
Cross multiply:
54πx = 6480π
Divide both sides by 54π to isolate for x:
x = 120°
Answer:
a) To determine the minimum sample size we need to use the formula shown in the picture 1.
E is the margin of error, which is the distance from the limits to the middle (the mean) of the confidence interval. This means that we have to divide the range of the interval by 2 to find this distance.
E = 0.5/2 = 0.25
Now we apply the formula
n = (1.645*0.80/0.25)^2 = 27.7 = 28
The minimum sample size would be 28.
b) To answer the question we are going to make a 90% confidence interval. The formula is:
(μ - E, μ + E)
μ is the mean which is 127. The formula for E is shown in the picture.
E = 0.80*1.645/√8 = 0.47
(126.5, 127.5)
This means that the true mean is going to be contained in this interval 90% of the time. This is why it doesn't seem possible that the population mean is exactly 128.
