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4 years ago

F(x) = 5x – 12 What is f (-4)please help im on a timer!!

Mathematics

1 answer:

Y_Kistochka [10]4 years ago

4 0

Answer:

f(-4)=-32

Step-by-step explanation:

Plug in -4 for x

f(-4)=5(-4)-12

Combine like terms

f(-4)=-20-12

f(-4)=-32

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Joan's Nursery specializes in custom-designed landscaping for residential areas. The estimated labor cost associated with a part

Gnoma [55]

Answer:

A) Null and alternative hypothesis

$H_0: \mu=2\\\\H_a:\mu\neq 2$

B) M = 2.2 hours

C) s = 0.52 hours

D) P-value = 0.255

E) At a significance level of 0.05, there is not enough evidence to support the claim that the mean tree-planting time significantly differs from two hours.

Step-by-step explanation:

This is a hypothesis test for the population mean.

The claim is that the mean tree-planting time significantly differs from two hours.

Then, the null and alternative hypothesis are:

$H_0: \mu=2\\\\H_a:\mu\neq 2$

The significance level is 0.05.

The sample has a size n=10.

The sample mean is M=2.2.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=0.52.

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

$s_M=\dfrac{s}{\sqrt{n}}=\dfrac{0.52}{\sqrt{10}}=0.1644$

Then, we can calculate the t-statistic as:

$t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{2.2-2}{0.1644}=\dfrac{0.2}{0.1644}=1.216$

The degrees of freedom for this sample size are:

$df=n-1=10-1=9$

This test is a two-tailed test, with 9 degrees of freedom and t=1.216, so the P-value for this test is calculated as (using a t-table):

$\text{P-value}=2\cdot P(t>1.216)=0.255$

As the P-value (0.255) is bigger than the significance level (0.05), the effect is not significant.

The null hypothesis failed to be rejected.

At a significance level of 0.05, there is not enough evidence to support the claim that the mean tree-planting time significantly differs from two hours.

Sample mean and standard deviation:

 $M=\dfrac{1}{n}\sum_{i=1}^n\,x_i\\\\\\M=\dfrac{1}{10}(1.7+1.5+2.6+. . .+2.3)\\\\\\M=\dfrac{22}{10}\\\\\\M=2.2\\\\\\s=\sqrt{\dfrac{1}{n-1}\sum_{i=1}^n\,(x_i-M)^2}\\\\\\s=\sqrt{\dfrac{1}{9}((1.7-2.2)^2+(1.5-2.2)^2+(2.6-2.2)^2+. . . +(2.3-2.2)^2)}\\\\\\s=\sqrt{\dfrac{2.4}{9}}\\\\\\s=\sqrt{0.27}=0.52\\\\\\$

3 0

3 years ago

Plzz helpppp meee.... i need the answer and steps really fast ...

blsea [12.9K]

Answer:

R = √2

α = π/4 or 45°

Step-by-step explanation:

R cos(2n + α)

Use angle sum formula:

R [cos(2n) cos α − sin(2n) sin α]

R cos(2n) cos α − R sin(2n) sin α

Match the coefficients:

R cos α = 1

R sin α = 1

Divide:

tan α = 1

α = π/4 or 45°

Solve for R:

R cos(π/4) = 1

R / √2 = 1

R = √2

4 0

3 years ago

The length of a rectangular picture frame is 2 inches longer than twice the width. If the perimeter of the frame is 34 inches, f

lyudmila [28]

The length, l, is 2 more than twice the width, w.
l= 2w+2 (2 more than twice w)
In a rectangle, we have two of the same lengths and two of the same widths.
2l+2w=34
Divide by 2 on each side.
l+w=17
We remember that l is 2w+2
Substituting that back in we get,
2w+2+w=17
3w+2=17
3w=15
w=5
We sub w back into l+w=17
l+5=17
l=12
The dimensions are 5 by 12 inches.

7 0

3 years ago

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Round the number to the nearest ten place: 1823

Flura [38]

Answer:

1820

Step-by-step explanation:

4 or less let it est 5 or more round up

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3 years ago

Which of the following expression is equivalent to a+(-b)

Leni [432]

Answer:

I can see any expressions

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3 years ago

F(x) = 5x – 12 What is f (-4)please help im on a timer!!​

F(x) = 5x – 12 What is f (-4)please help im on a timer!!