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2 years ago

(21-3) x (7+2) ÷ (12-4) * PLS HELP

Mathematics

2 answers:

Pachacha [2.7K]2 years ago

8 0

Answer:

81x/4

Step-by-step explanation:

liubo4ka [24]2 years ago

7 0

Answer:

hey i know i anit answering this but try caucolaator soup if not make a smiller question and i will give the answer.

Step-by-step explanation:

20.25

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Answer it and show your work. Which letter choice is it.

ivanzaharov [21]

Answer:

b = 55 degrees

Step-by-step explanation:

The angles 30, a, b and 45 must sum up to 180 degrees

Subtracting (30 + 45) from both sides leaves us with a + b = 105 degrees.

But b = a + 5. Substituting a + 5 in the equation above yields

a + a + 5 = 105 degrees, so that

2a = 100 degrees, and a = 50 degrees. Then b = a + 5, or b = 55 degrees.

7 0

2 years ago

**22 POINTS** Please solve this fraction as a difference

Ghella [55]

Answer:

$\dfrac{x}{4}-\dfrac{7}{12}$

Step-by-step explanation:

The fraction is the equivalent of ...

$\dfrac{1}{12}{(3x-7)$

and the distributive property applies.

$=\dfrac{1}{12}(3x)-\dfrac{1}{12}(7)\\\\=\dfrac{3\cdot x}{3\cdot 4}-\dfrac{7}{12}\\\\=\dfrac{x}{4}-\dfrac{7}{12}$

3 0

2 years ago

F(3)= 5x^2 - 4x + 9<br> evaluate this quadratic function

Neporo4naja [7]

Answer:

$f(3) = 38$

Step-by-step explanation:

Given the quadratic function

$f\left(x\right)=\:5x^2\:-\:4x\:+\:9$

Evaluating the quadratic function

$f\left(x\right)=\:5x^2\:-\:4x\:+\:9$

substitute x = 3

$f\left(3\right)=\:5\left(3\right)^2\:-\:4\left(4\right)\:+\:9$

$f(3) = 45-16+9$

$f(3) = 38$

Therefore,

$f(3) = 38$

6 0

1 year ago

The realtor and her clients do not know the average home sale price for all of Guelph (500 was actually just a guess). However,

strojnjashka [21]

Answer:

a) The 99% confidence interval would be given by (346.708;453.292)

b) The 99% confidence interval would be given by (338.445;461.555)

Step-by-step explanation:

1) Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

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".

$\bar X=400$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=80$ represent the population standard deviation

n=15 represent the sample size

2) Part a

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

Now we have everything in order to replace into formula (1):

$400-2.58\frac{80}{\sqrt{15}}=346.708$

$400+2.58\frac{80}{\sqrt{15}}=453.292$

So on this case the 99% confidence interval would be given by (346.708;453.292)

3) Part b

For this case we don't know the population deviation so we need to use the t distribution instead the normal standard distribution.

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

We need to find the degrees of freedom first df=n-1=15-1=14

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,14)".And we see that $t_{\alpha/2}=2.98$

Now we have everything in order to replace into formula (1):

$400-2.98\frac{80}{\sqrt{15}}=338.445$

$400+2.98\frac{80}{\sqrt{15}}=461.555$

So on this case the 99% confidence interval would be given by (338.445;461.555)

4 0

2 years ago

3. The backyard of a home is a rectangle 25m by 30m. A garden of uniform width is to be

KiRa [710]

Answer:

Part A

The width of the garden is approximately 3.987 meters

Part B

Please find attached the drawing of the solution

Step-by-step explanation:

Part A

The given parameters are;

The dimensions of the backyard of the home = 25 m by 30 m

The width of the garden to be built in the yard = Uniform width

The shape of the grass left inside = Rectangular

The area of the grass at the center = The area of the garden

Let 'x' represent the width of the garden, we have;

The length of the rectangular grass area at the center, l = 30 - 2·x

The width of the rectangular area of grass at the center, w = 25 - 2·x

The area of the rectangular backyard, A = 30 m × 25 m = 750 m²

The area of the rectangular backyard, A = (The area of the garden) + (The area of the rectangle of grass inside)

The area of the rectangle of grass, GA = (30 - 2·x)·(25 - 2·x) = The area of the garden

The area of the rectangular backyard, A = 750 = (30 - 2·x)·(25 - 2·x) + (30 - 2·x)·(25 - 2·x) = 2 × (30 - 2·x)·(25 - 2·x) = 8·x² - 220·x + 1,500

∴ 750 = 8·x² - 220·x + 1,500

8·x² - 220·x + 1,500 - 750 = 0

8·x² - 220·x + 750 = 0

x = (220 ± √(220² - 4 × 8 × 750))/(2 × 8)

x ≈ 23.513, or x = 3.987

When x = 25.513, the width of the rectangle of grass inside, w = 25 - 2 × 23.513 = -22.026, which is not a natural (physically possible)

Therefore, the possible width of the garden, x ≈ 3.987

Part B

The drawing of the solution created with MS Visio is attached

6 0

1 year ago