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2 years ago

Which point is the solution to the system of linear equations shown below?

Mathematics

2 answers:

PilotLPTM [1.2K]2 years ago

8 0

The answer is:
D (2,-1)

iren [92.7K]2 years ago

4 0

The answer should be D: (2,-1)

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PLS HELP it's DUE TODAY

charle [14.2K]

Answer:

Third answer

Step-by-step explanation:

1 x 7 = 7

36 x 7 = 252

6 0

3 years ago

Read 2 more answers

23. A certain type of gasoline is supposed to have a mean octane rating of at least 90. Suppose measurements are taken on of 5 r

Nostrana [21]

Answer:

a) $p_v =P(Z$

b) Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

c) $P(\bar X >90)=1-P(Z$

$1-P(Z$

d) For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

Step-by-step explanation:

Previous concepts and data given

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

We can calculate the sample mean and deviation with the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s=\sqrt{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$\bar X=88.96$ represent the sample mean

$s=1.011$ represent the sample standard deviation

n=5 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is less than 90, the system of hypothesis would be:

Null hypothesis: $\mu \geq 90$

Alternative hypothesis: $\mu < 90$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{88.96-90}{\frac{0.8}{\sqrt{5}}}=-2.907$

Part a

P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=5-1 = 4$

Then since is a left tailed test the p value would be:

$p_v =P(Z$

Part b

Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

Part c

We want this probability:

$P(\bar X$

The best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}$

If we apply this formula to our probability we got this:

$P(\bar X >90)=1-P(Z$

$1-P(Z$

Part d

For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

7 0

3 years ago

Solve: 63z2+61z=−6. Multiple answers

vodomira [7]

z = -1/9 , -6/7

Have a nice day!

6 0

2 years ago

Plz do number 19 and determine if it’s possible or not

astraxan [27]

we have a rule in forming triangle.

that sum of any two sides is must be greater than the third side.

here we have three sides measure 9m,9m, and 9m

we have to add up any two sides here .

so 9+9=18 .

where 18 is greater than the third side 9.

so it is possible to form triangle with the given length sides.

4 0

3 years ago

Read 2 more answers

Solve for c.<br> -c/2+43 = 50

noname [10]

$\huge\text{Hey there!}$

$\mathsf{-\dfrac{c}{2}+43=50}$

$\large\text{SUBTRACT 43 to BOTH SIDES}$

$\mathsf{-\dfrac{c}{2}+43-43=50-43}$

$\large\textsf{CANCEL out: 43 - 43 because that gives you 0}$

$\large\textsf{KEEP: 50 - 43 because it helps solve for the c-value}$

$\mathsf{50 - 43 = \bf 7}$

$\large\text{NEW EQUATION: }\mathsf{-\dfrac{c}{2}=7}$

$\large\textsf{MULTIPLY }\mathsf{\dfrac{2}{-1}}\large\textsf{ to BOTH SIDES}$

$\mathsf{\dfrac{2}{-1}\times-\dfrac{c}{2}= \dfrac{2}{-1}\times7}$

$\large\textsf{CANCEL out: your RIGHT SIDE of the equation because that gives}\\\large\textsf{you 1}$

$\large\textsf{KEEP: }\mathsf{\dfrac{2}{-1}\times7}\large\textsf{ because that helps solve for the c-value}$

$\uparrow\large\text{SIMPLIFY THE EQUATION ABOVE \& YOU HAVE YOUR}\\\large\text{C-VALUE}\uparrow$

$\boxed{\boxed{\large\text{ANSWER: \huge\bf c = -14}}}\huge\checkmark$

$\large\text{Good luck on your assignment and enjoy your day!}$

~ $\frak{Amphitrite1040:)}$

5 0

3 years ago