The first equation will turn into -18x -6y = -18, and the second equation will turn into 14x + 6y = 18. The y terms will cancel out when you add the equations together.

8 0

3 years ago

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A number is divided by four. The result is added to five. This result is multiplied by three to give 27. What is the number?

Damm [24]

The answer is 16

Explanation:16/4=4

4+5=9

9*3=27

3 0

3 years ago

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An electronics company just finished designing a new tablet computer and is interested in estimating its battery-life. A random

Alika [10]

Answer:

$6 \pm 2.861(0.3354)$

Step-by-step explanation:

We have the standard deviation for the sample, so we use the t-distribution to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 20 - 1 = 19

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 19 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.99}{2} = 0.995$ . So we have T = 2.861.

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 2.861\frac{1.5}{\sqrt{20}} = 2.861(0.3354)$

In which s is the standard deviation of the sample and n is the size of the sample.

The format of the confidence interval is:

$S_{M} \pm M$

In which $S_{M}$ is the sample mean

$6 \pm 2.861(0.3354)$

7 0

3 years ago