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3 years ago

(x-5)1/2+5=2 (x-5)1/2=-3 [(x-5)^1/2]^2=(-3)^2

Mathematics

1 answer:

Studentka2010 [4]3 years ago

3 0

Answer:

x = 14

Step-by-step explanation:

You want to solve for x, right?

(x-5)^(1/2)+5=2

You have it right so far.

(x - 5)^(1/2) = -3

(x - 5) = (-3)^2

x - 5 = 9

x = 9 + 5 = 14

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The measures of two complementary angles are in the ratio 8:1. how many degrees are in the larger angle?

djverab [1.8K]

Since the measures of the two angles are in the ratio 8:1, this means the bigger angle's is 8x and the smaller angle is x. Since they are complementary, they add to 90°, so you create the equation 8x+x=90°. This can be simplified to 9x=90°. Then, you divide 90 by 9 to get 10. This means x=10. Next, you replace x with 10 to find the measure of the bigger angle. 8x10=80, so the larger angle is 80°.

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4 years ago

in a random sample of 200 people, 154 said that they watched educational television. fine the 90% confidence interval of the tru

melisa1 [442]

Answer:

[0.7210,0.8189] = [72.10%, 81.89%]

Step-by-step explanation:

The sample size is

n = 200

the proportion is

p = 154/200 = 0.77

Since both np ≥ 10 and n(1-p) ≥ 10

We can approximate this discrete binomial distribution with the continuous Normal distribution. As the sample size is large enough, not applying the continuity correction factor makes no significant difference.

The approximation would be to a Normal curve with this parameters:

Mean

p = 0.77

Standard deviation

$\bf s=\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.77*0.23}{200}}=0.0298$

The 90% confidence interval for the proportion would be then

$\bf [0.77-z^*0.0298, 0.77+z^*0.0298]$

where $\bf z^*$ is the 10% critical value for the Normal N(0,1) distribution , this is a value such that the area under the N(0,1) curve outside the interval $\bf [-z^*,z^*]$ is 10%=0.1

We can either use a table, a calculator or a spreadsheet to get this value.

In Excel or OpenOffice Calc we use the function

NORMSINV(0.95) and we get a value of 1.645

The 90% confidence interval for the proportion is then

$\bf [0.77-1.645^*0.0298, 0.77+1.645^*0.0298]=[0.7210,0.8189]$

This means there is a 90% probability that the proportion of people who watch educational television is between 72.10% and 81.89%

If the television company wanted to publicize the proportion of viewers, do you think it should use the 90% confidence interval?

Yes, I do.

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3 years ago

Factor completely 2x3 + x2 - 18x – 9.

lys-0071 [83]

$2x^3+x^2-18x-9=x^2(2x+1)-9(2x+1)\\\\=(2x+1)(x^2-9)=(2x+1)(x^2-3^2)\\\\=(2x+1)(x-3)(x+3)$

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Alexxx [7]

Answer:

AB=AC

X²+8 =33

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X²=25.

X=√25

X=5

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