Solve either equation for either variable. Since the second one has y on its own, the easiest choice is to solve that for y.
-5x + y = 13 ⇒ y = 5x + 13
Now substitute this into the other equation to eliminate y and rewrite it entirely in terms of x :
-3x + 3y = 3 ⇒ -3x + 3 (5x + 13) = 3
Simplify and solve for x :
-3x + 15x + 39 = 3
12x = -36
x = -3
Substitute this into either original equation to solve for y. Plugging x = -3 into the first equation would give
-3 (-3) + 3y = 3
9 + 3y = 3
3y = -6
y = -2
So the solution to the system of equations is (x, y) = (-3, -2).
Answer:
make sure that sentence that comes before the colon is a complete, sentence
Step-by-step explanation:
One way to test whether you have used a colon correctly is to delete the information after the colon.
Answer:
the first and the second answer
Step-by-step explanation:
Answer:150
Step-by-step explanation:
The 90% confidence interval for the population mean of the considered population from the given sample data is given by: Option C: [130.10, 143.90]
<h3>
How to find the confidence interval for population mean from large samples (sample size > 30)?</h3>
Suppose that we have:
- Sample size n > 30
- Sample mean =

- Sample standard deviation = s
- Population standard deviation =

- Level of significance =

Then the confidence interval is obtained as
- Case 1: Population standard deviation is known

- Case 2: Population standard deviation is unknown.

For this case, we're given that:
- Sample size n = 90 > 30
- Sample mean =
= 138 - Sample standard deviation = s = 34
- Level of significance =
= 100% - confidence = 100% - 90% = 10% = 0.1 (converted percent to decimal).
At this level of significance, the critical value of Z is:
= ±1.645
Thus, we get:
![CI = \overline{x} \pm Z_{\alpha /2}\dfrac{s}{\sqrt{n}}\\CI = 138 \pm 1.645\times \dfrac{34}{\sqrt{90}}\\\\CI \approx 138 \pm 5.896\\CI \approx [138 - 5.896, 138 + 5.896]\\CI \approx [132.104, 143.896] \approx [130.10, 143.90]](https://tex.z-dn.net/?f=CI%20%3D%20%5Coverline%7Bx%7D%20%5Cpm%20Z_%7B%5Calpha%20%2F2%7D%5Cdfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D%5C%5CCI%20%3D%20138%20%5Cpm%201.645%5Ctimes%20%5Cdfrac%7B34%7D%7B%5Csqrt%7B90%7D%7D%5C%5C%5C%5CCI%20%5Capprox%20138%20%5Cpm%205.896%5C%5CCI%20%5Capprox%20%5B138%20-%205.896%2C%20138%20%2B%205.896%5D%5C%5CCI%20%5Capprox%20%5B132.104%2C%20143.896%5D%20%5Capprox%20%5B130.10%2C%20143.90%5D)
Thus, the 90% confidence interval for the population mean of the considered population from the given sample data is given by: Option C: [130.10, 143.90]
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