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3 years ago

{2x+7y=2 {y= -2x-1 Am I right?

Mathematics

1 answer:

vampirchik [111]3 years ago

6 0

<span>Okay so we have. 2x + 7y = 2 y = - 2x - 1 Rearranging the second expression we have y + 2x = -1; So 2x + y = -1 2x + 7y = 2 2x + y = -1 Subtracting both eqns we have (2x - 2x) + (7y-y) = 2-(-1). So we have 6y =3; y = 0.5 Substituting into second eqn we have 2x + 0.5 = -1. 2x = -1-0.5=-1.5. Hence x = --0.75. So we have to check for consistency if we would confirm the expression. So Substiting values of x and y into the first eqn we have 2(-0.75) + 7(0.5) = -1.5 + 3.5 =2. And into the second eqn we have 2(-0.75) + 0.5 =-1.5 + 0.5 =-1. So, yes! You are dead right.</span>

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the performance score of 10 adults is recorded, and the results are 83 87 90 92 93 100 104 111 115 121 find the standard deviati

luda_lava [24]

Answer:

The standard deviation of the data set is $\sigma = 12.7906$ .

Step-by-step explanation:

The Standard Deviation is a measure of how spread out numbers are. Its symbol is σ (the greek letter sigma)

To find the standard deviation of the following data set

$\begin{array}{cccccccc}83&87&90&92&93&100&104&111\\115&121&&&&&&\end{array}$

we use the following formula

$\sigma = \sqrt{ \frac{ \sum{\left(x_i - \overline{X}\right)^2 }}{n-1} }$

Step 1: Find the mean $\left( \overline{X} \right)$ .

The mean of a data set is the sum of the terms divided by the total number of terms. Using math notation we have:

$Mean = \frac{Sum ~ of ~ terms}{Number ~ of ~ terms}$

$Mean = \frac{Sum ~ of ~ terms}{Number ~ of ~ terms}=\frac{83+87+90+92+93+100+104+111+115+121}{10} \\\\Mean = \frac{996}{10} =\frac{498}{5}=99.6$

Step 2: Create the below table.

Step 3: Find the sum of numbers in the last column to get.

$\sum{\left(x_i - \overline{X}\right)^2} = 1472.4$

Step 4: Calculate σ using the above formula.

$\sigma = \sqrt{ \frac{ \sum{\left(x_i - \overline{X}\right)^2 }}{n-1} } = \sqrt{ \frac{ 1472.4 }{ 10 - 1} } \approx 12.7906$

3 0

3 years ago

Primitive function for:<br><br> 1. f(x)=4e2x+e−x, sådan att F(0)=2

Free_Kalibri [48]

The primitive function for $f(x) = 4e^{2x} + e^{-x}$ is given by it's indefinite integral.

To calculate it, recall:

$\frac{d}{dx}e^{ax}=ae^{ax}$

$\int c f(x)dx = c\int f(x)dx$

Let's begin

$\int 4e^{2x}+e^{-x}dx \\4\int e^{2x}dx+ \int e^{-x}dx\\4\frac{e^{2x}}{2}+\frac{e^{-x}}{-1} + c\\$

$F(x) = 2e^{2x}-e^{-x} +c$

To find the costant, we just need to use the fact that $F(0)=2$

$F(0) = 2 \\4e^{0}+e^{0} + c =2\\5+c =2\\c=-3$

Therefore,

$\boxed{F(x) = 2e^{2x} - e^{-x} -3 }$

6 0

2 years ago

What is the value of x in the equation x3=27125 ?

alina1380 [7]

Answer:

x = 30.0462

Step-by-step explanation:

Divide each side by 3 to cancel out the 3 next to x. It should now look like this: x = 30.0462

I hope this helps!

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3 years ago

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Morgarella [4.7K]

Answer:

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Step-by-step explanation:

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2 years ago

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Vinil7 [7]

8/8 I’m pretty that what is it

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