Need Help Please!!!!!

How many solutions are there to the following system of equations?

sweet [91]

$4x-8y=0 \\
\underline{-3x+8y=-7} \\
4x-3x=0-7 \\
x=-7 \\ \\
4x-8y=0 \\
4 \times (-7)-8y=0 \\
-28-8y=0 \\
-8y=28 \\
y=\frac{28}{-8} \\
y=-\frac{7}{2} \\ \\
 \left \{ {{x=-7} \atop {y=-\frac{7}{2}}} \right.$

There is one solution to this system of equations. The answer is B.

6 0

3 years ago

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(16 divided by 4) x (7-4)

zavuch27 [327]

4 x 3 = 12
12 would be the answer

4 0

3 years ago

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An HP laser printer is advertised to print text documents at a speed of 18 ppm (pages per minute). The manufacturer tells you th

aliya0001 [1]

Answer:

0.227 = 22.7% probability that the mean printing speed of the sample is greater than 18.12 ppm.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Mean of 17.42 ppm and a standard deviation of 3.25 ppm.

This means that $\mu = 17.42, \sigma = 3.25$

Sample of 12:

This means that $n = 12, s = \frac{3.25}{\sqrt{12}}$

Find the probability that the mean printing speed of the sample is greater than 18.12 ppm.

This is 1 subtracted by the p-value of Z when X = 18.12.

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$Z = \frac{18.12 - 17.42}{\frac{3.25}{\sqrt{12}}}$

$Z = 0.75$

$Z = 0.75$ has a pvalue of 0.773.

1 - 0.773 = 0.227

0.227 = 22.7% probability that the mean printing speed of the sample is greater than 18.12 ppm.

4 0

3 years ago

a landscaper is supposed to plant pine trees, oak trees, and elm trees in a ratio of 48:12:120. At this time, the landscaper onl

iogann1982 [59]

Answer:

Step-by-step explanation:

Coniferous trees keep their needles all year with the exception of tamarack. They are good trees to plant for privacy and wind breaks or shelterbelts

Pines include native white, red, and jack. They have long needles.

Spruces, black and white, and firs. They have short needles. They are important sources of wood fiber in northern Minnesota, and are excellent choices for windbreaks or shelterbelts.

Cedars include white or red. Cedars have scaled needles. Smaller than pines and spruces, cedars can provide wildlife cover and food.

5 0

2 years ago

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Write the opposite of the situation:

Assoli18 [71]

Answer:

-8 yd. lost in football

Step-by-step explanation:

8 0

3 years ago