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2 years ago

The value of x is ?

Mathematics

1 answer:

allsm [11]2 years ago

5 0

Answer: X = 42

Steps:
(3x + 12) + x = 180
3x + 12 + x = 180
4x + 12 = 180
4x = 180 - 12
4x = 168
x = 168/4
x = 42

Check:
(3x + 12) + x = 180
3x + 12 + x = 180
3(42) + 12 + 42 = 180
126 + 12 + 42 = 180
180 = 180 ✅

I would appreciate the brainliest if this was correct and had helpful & clear steps! :)

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Select the equivalent expression. (6-4.8-7)-° -2

dalvyx [7]

I think the answer is -7.8

4 0

3 years ago

The following table shows the percent increase of donations made on behalf of a non-profit organization for the period of 1984 t

pashok25 [27]

Giving the table below which shows the percent increase of donations made on behalf of a non-profit organization for the period of 1984 to 2003.

Year: 1984 1989 1993 1997 2001 2003

Percent: 7.8 16.3 26.2 38.9 49.2 62.1

The scatter plot of the data is attached with the x-axis representing the number of years after 1980 and the y-axis representing the percent increase of donations made on behalf of a non-profit organization.

To find the equation for the line of regression where the x-axis representing the number of years after 1980 and the y-axis representing the percent increase of donations made on behalf of a non-profit organization.
$\begin{center}
\begin{tabular}{ c| c| c| c| }
 x & y & x^2 & xy \\ [1ex] 
 4 & 7.8 & 16 & 31.2 \\ 
 9 & 16.3 & 81 & 146.7 \\ 
13 & 26.2 & 169 & 340.6 \\ 
17 & 38.9 & 289 & 661.3 \\ 
21 & 49.2 & 441 & 1,033.2 \\ 
23 & 62.1 & 529 & 1,428.3 \\ [1ex]
\Sigma x=87 & \Sigma y=200.5 & \Sigma x^2=1,525 & \Sigma xy=3,641.3 
\end{tabular}
\end{center}$

Recall that the equation of the regression line is given by
$y=a+bx$
where
$a= \frac{(\Sigma y)(\Sigma x^2)-(\Sigma x)(\Sigma xy)}{n(\Sigma x^2)-(\Sigma x)^2} = \frac{200.5(1,525)-87(3,641.3)}{6(1,525)-(87)^2} \\ \\ = \frac{305,762.5-316793.1}{9,150-7,569} = \frac{-11,030.6}{1,581} =-6.977$
and
$b= \frac{n(\Sigma xy)-(\Sigma x)(\Sigma y)}{n(\Sigma x^2)-(\Sigma x)^2} = \frac{6(3,641.3)-(87)(200.5)}{6(1,525)-(87)^2} \\ \\ = \frac{21,847.8-17,443.5}{9,150-7,569} = \frac{4,404.3}{1,581} =2.7858$

Thus, the equation of the regresson line is given by
$y=-6.977+2.7858x$

The graph of the regression line is attached.

Using the equation, we can predict the percent donated in the year 2015. Recall that 2015 is 35 years after 1980. Thus x = 35.

The percent donated in the year 2015 is given by
$-6.977+2.7858(35)=-6.977+97.503=90.526$

Therefore, the percent donated in the year 2015 is predicted to be 90.5

7 0

3 years ago

For which inequality would x = 8 not be a solution?4x + 3 > 09x - 5 < 100x + 4 ≤ 1072 ÷ x ≥ 4

galina1969 [7]

Given:

Given the inequalities:4

$\begin{gathered} 4x+3>0 \\ 9x-5$

Required: Identify the inequality in which x = 8 is a solution.

Explanation:

Substitute 8 for x in each inequality and check whether it satisfies the inequality.

Consider 4x + 3 > 0.

$4\cdot8+3=35>0$

So, x = 8 satisfies the inequality 4x + 3 > 0.

Consider 9x - 5 < 100.

$9\cdot8-5=67$

So, x = 8 satisfies the inequality 9x - 5 < 100.

Consider x + 4 ≤ 10.

$8+4=12>10$

So, x = 8 not satisfies the inequality.

Consider 72 ÷ x ≥ 4.

$72\div8=9\ge4$

So, x = 8 satisfies the inequality.

Final Answer: The inequality in which x = 8 is not a solution is x + 4 ≤ 10.

5 0

1 year ago

Two airplanes leave an airport at the same time, the first headed due north and the second at a bearing of N42^ E . At 2:00PM, t

Leno4ka [110]

Answer:

The two airplanes are about 330miles apart.

Step-by-step explanation:

The diagram interpreting the question has been attached to this response.

As shown in the diagram,

i. the airplanes leave at point C.

ii. at 2.00pm the first and second airplanes are at points A and B respectively, where they are 312miles and 487miles away from the starting point C in directions due north and N42E from the point C.

iii. the points A, B and C form a triangle with sides a, b and c.

To solve for the value of c which is the distance between the two planes at 2.00pm, the cosine rule is used.

c² = a² + b² - 2abcosC --------------(i)

where;

b = 312miles

a = 487miles

C = 42°

Substitute these values into equation (i) and solve as follows;

c² = (487)² + (312)² - 2(312)(487)cos(42)

c² = (237169) + (97344) - 303888cos(42)

c² = (237169) + (97344) - 303888(0.7431)

c² = 334513 - 225819.1728

c² = 108693.8272

Take the square root of both sides

√c² = √108693.8272

c = 329.69

c ≅ 330miles

Therefore, the two airplanes are far apart by 330miles

3 0

3 years ago

We measure the diameters for a random sample of 25 oak trees in a neighbourhood. Diameters of oak trees in the neighbourhood fol

jarptica [38.1K]

Answer:

The required confidence inteval = 94.9%.

Step-by-step explanation:

Confidence interval: Mean ± Margin of error

Given: A confidence interval for the true mean diameter of all oak trees in the neighbourhood is calculated to be (36.191, 42.969).

i.e. Mean + Margin of error = 42.969 (i)

Mean - Margin of error = 36.191 (ii)

Adding (i) and (ii), we get

$2Mean =79.16\\\\\Rightarrow\ Mean= 39.58$

Margin of error = 42.969-39.58 [from (i)]

= 3.389

Margin of error = $t^* \dfrac{\sigma}{\sqrt{n}}$

here n= 25 $, \ \sigma=8.25$

i.e.

$3.389=t^*\dfrac{8.25}{5}\\\\\Rightarrow\ t^* = \dfrac{3.389}{1.65}\\\\\Rightarrow\ t^* =2.0539 \$

Using excel function 1-TDIST.2T(2.054,24)

The required confidence inteval = 94.9%.

7 0

3 years ago