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3 years ago

Help me out with this one please

Mathematics

2 answers:

Anna11 [10]3 years ago

8 0

Answer:

5) x = -1

6) x = 2

Step-by-step explanation:

5) 5 + 2x + 6 = x + 10

2x + 11 = x + 10

2x + 1 = x

1 = -x

-1 = x

6) (9x + 7) + (-3x + 20) = 39

6x + 27 = 39

6x = 12

x = 2

dlinn [17]3 years ago

8 0

Answer:

For question 5, x= -1

Step-by-step explanation:

Segment Addition Postulate = ab+bc=ac

For Question 5,

(a) + (b) = (c)

5+2x + 6 = x+10

5+2x+6=x+10

To solve that,

5+2x+6=x+10

Add 5+6

11+2x=x+10

Subtract 11 from both sides

2x= x-1

x-1=2x

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If you take four away four my number then divide the answer by three you will get 11

Svetlanka [38]

37. 37-4=33 33÷3=11 hope i helped

7 0

3 years ago

A researcher examines 27 water samples for iron concentration. The mean iron concentration for the sample data is 0.802 cc/cubic

Delvig [45]

Answer:

90% confidence interval for the population mean iron concentration is [0.771 , 0.832].

Step-by-step explanation:

We are given that a researcher examines 27 water samples for iron concentration. The mean iron concentration for the sample data is 0.802 cc/cubic meter with a standard deviation of 0.093.

Firstly, the pivotal quantity for 90% confidence interval for the population mean iron concentration is given by;

P.Q. = $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean iron concentration = 0.802 cc/cubic meter

s = sample standard deviation = 0.093

n = number of water samples = 27

$\mu$ = population mean

Here for constructing 90% confidence interval we have used t statistics because we don't know about population standard deviation.

So, 90% confidence interval for the population mean, $\mu$ is ;

P(-1.706 < $t_2_6$ < 1.706) = 0.90 {As the critical value of t at 26 degree of

freedom are -1.706 & 1.706 with P = 5%}

P(-1.706 < $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ < 1.706) = 0.90

P( $-1.706 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X - \mu}$ < $1.706 \times {\frac{s}{\sqrt{n} } }$ ) = 0.90

P( $\bar X -1.706 \times {\frac{s}{\sqrt{n} }$ < $\mu$ < $\bar X +1.706 \times {\frac{s}{\sqrt{n} }$ ) = 0.90

90% confidence interval for $\mu$ = [ $\bar X -1.706 \times {\frac{s}{\sqrt{n} }$ , $\bar X +1.706 \times {\frac{s}{\sqrt{n} }$ ]

= [ $0.802 -1.706 \times {\frac{0.093}{\sqrt{27} }$ , $0.802 +1.706 \times {\frac{0.093}{\sqrt{27} }$ ]

= [0.771 , 0.832]

Therefore, 90% confidence interval for the population mean iron concentration is [0.771 , 0.832].

4 0

3 years ago

Identify the type of observational study (cross-sectional, retrospective, or prospective) described below. A research company

shepuryov [24]

Answer:

Cross Sectional

Step-by-step explanation:

A cross sectional is one in which an association is developed between a risk factor or an outcome.

In the given question the device is used to record the viewing habits of about 2500 households, and the data collected today will be used to determine the proportion of households tuned to a particular news program. There will be risk factor in today's research with the future developed program which will the outcome.

For example there are 20 students in my class who cannot write. So I develop a program to help them write. But the next year there may not be any student who would require such help.So there's a risk factor associated with the outcome.

Cross sectional results are recorded in a two ways table showing do's and don'ts.

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2 years ago

Which model does the graph represent?

larisa86 [58]

Answer:

Step-by-step explanation:

A models an exponentially increasing function.

B models an exponentially decreasing function.

C models a "bell" curve, similar to the one shown.

D models a "logistic" function, an s-shaped curve that smoothly transitions between two horizontal asymptotes.

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