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4 years ago

9x+8y=6-7x=14what is the system of equation by elimination?

1 answer:

5 0

9x-7x= 2x
because both are x's now u cant add nor subtract anything to Y so just leave it alone but u can add 6+14

2x+8y=20

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A laptop producing company also produces laptop batteries, and claims that the batteries

gregori [183]

Answer:

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours. (P-value = 0).

The null and alternative hypothesis are:

$H_0: \mu=4\\\\H_a:\mu< 4$

Step-by-step explanation:

The question is incomplete: To test this claim a sample or population standard deviation is needed.

We will estimate that the sample standard deviation is 2 hours, and use a t-test to test that claim.

NOTE (after solving): The difference between the sample mean and the mean of the null hypothesis is big enough to reject the null hypothesis, even when we have a sample standard deviation of 3.5 hours, which can be considered bigger than the maximum standard deviation for the sample.

This is a hypothesis test for the population mean.

The claim is that the batteries power the laptops for significantly less than 4 hours.

Then, the null and alternative hypothesis are:

$H_0: \mu=4\\\\H_a:\mu< 4$

The significance level is 0.05.

The sample has a size n=500.

The sample mean is M=3.5.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=2.

The estimated standard error of the mean is computed using the formula:

$s_M=\dfrac{s}{\sqrt{n}}=\dfrac{2}{\sqrt{500}}=0.0894$

Then, we can calculate the t-statistic as:

$t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{3.5-4}{0.0894}=\dfrac{-0.5}{0.0894}=-5.5902$

The degrees of freedom for this sample size are:

$df=n-1=500-1=499$

This test is a left-tailed test, with 499 degrees of freedom and t=-5.5902, so the P-value for this test is calculated as (using a t-table):

$P-value=P(t$

As the P-value (0) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours.

5 0

3 years ago

The length of a rectangle is 4 more than it's width. Write an equation that will determine the dimensions if the area of the rec

Firdavs [7]

Answer: The equation is W^2 + 4W - 96= 0

{Please note that ^2 means raised to the power of 2}

Step-by-step explanation: We have been given hints as to the measurement of the length and width of the rectangle. The length is given as four more than the width. What that means is that whatever is the width, we simply add four to get the measurement of the length. Therefore if the width is W, then the length is W + 4.

That is,

L = W + 4 and

W = W

Also we have the area given as 96.

Remember that the area of a rectangle is given as

Area = L x W.

In this question, the Area is expressed as

Area = (W + 4) x W

96 = W^2 + 4W

Subtract 96 from both sides of the equation and we have

W^2 + 4W - 96 = 0.

We now have a quadratic equation from which we can determine the dimensions of the rectangle

5 0

3 years ago

It is about 1.62×10⁶ miles from Venus to Earth. It is about 5.4×10⁷ from Earth to Mars. How far is it total from Venus to Earth

Lubov Fominskaja [6]

Answer:

-5.238- $10^{7}$

Since the exponent of the scientific notation is positive, move the decimal point 6 places to the right.

1620000

Step-by-step explanation:

Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the

10 . If the decimal is being moved to the right, the exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.

Hope this helps :)

4 0

2 years ago

O I WILL VENMO $10 please help

bekas [8.4K]

Answer:

See there is x° see the angle is right angle so

X = 90°

Y = 270°

8 0

3 years ago

How many unique roots are possible in a seventh-degree polynomial

andreev551 [17]

Answer:

A. 7

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers