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2 years ago

Alguien me pude decir una adivinanza o historia q la solución sea una ecuación de segundo grado completa????

Mathematics

1 answer:

Hitman42 [59]2 years ago

4 0

Answer:

Una ecuación de segundo grado completa es algo como:

y = a*x^2 + b*x + c

Un problema tipico que usa ecuaciones de este tipo es algo que nos haga multiplicar dos términos como h*(x + k) y n*(x + j)

Donde h, k, n, y j son números reales.

Entonces planteemos el siguiente caso.

"Juan tiene una tabla rectangular, de tal forma que su largo es (x + 3cm), y el ancho es igual a dos veces su largo, si sabemos que el área de esta tabla es 95 cm^2 ¿cuál es el valor de x?"

Acá hay que recordar que para un rectángulo de largo L y ancho W, el área es:

A = L*W

En este caso tendremos:

L = (x + 3cm)

Y el ancho es dos veces eso, entonces:

W = 2*(x + 3cm)

Entonces el area de esta tabla se escribirá como:

A = (x + 3cm)*2*(x + 3cm)

Ahora solo tenemos que expandir eso:

A = 2*x^2 + 12cm*x + 18cm^2

Ahora sabemos que el area de esta tabla es 95cm^2

Entonces:

95cm^2 = 2*x^2 + 12cm*x + 18cm^2

0 = 2*x^2 + 12cm*x + (18cm^2 - 95cm^2)

0 = 2*x^2 + 12cm*x - 77 cm^2

Esta es una ecuación de segundo grado completa, la cual deberiamos resolver para encontrar el valor de x como se nos pide en el problema.

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A number cube with faces labeled 1 through 6 is rolled 200 times. About how many times would you expect to roll an even number?

Sergio039 [100]

Answer:

The theoretical probability is smaller than the relative frequency

Step-by-step explanation:

6-sided cube rolled 200 times

Probability of an even number is 1/2= 0.5

200*1/2= 100- theoretical probability

Experimental frequency= 115

Relative frequency= 115/200= 0.575

0.575 > 0.5

The theoretical probability is smaller than the relative frequency

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3 years ago

Divide the following polynomial using synthetic division, then place the answer in the proper location on the grid. Write answer

MAXImum [283]

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3 years ago

Read 2 more answers

Tina is saving to buy a notebook computer. She has two options. The first option is to put S200 away initially and save $10 ever

BigorU [14]

The equation for the first option is Y=10x + 200
The equation for the second option is Y=30x + 100

X = one month
To find when they would be the same about you have to set the equations equal to each other

10x + 200 = 30x + 100
-10x -100 -10x -100

100= 20x

5 = x

After five months she would save the same amount. To find how much is saved you have to plug in 5 for x in one of the equations. You can always double-check 5 by plugging it in both equations and making sure you get the same answer

Y= 10(5) + 200 = 250

Y= 30(5) + 100 = 250

She would have saved $250 after five months by using either method

6 0

3 years ago

£35.50 for the first day then £18.25 for each extra day the total cost of hiring the machine was £ 163.25 how many day dose Mart

BabaBlast [244]

y = number of days
35.50 + 18.25 y = 163.25

18.25 y = 163.25 - 35.50

18.25y = 127.75

y = 127.75 / 18.25

y = 7

so Martin has hired the machine for 8 days

( first day paid 35.50), then 7 days for 18.25

8 0

3 years ago

In an examination of purchasing patterns of shoppers, a sample of 16 shoppers revealed that they spent, on average, $54 per hour

Lesechka [4]

Answer:

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

Step-by-step explanation:

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".

$\bar X=54$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=21$ represent the sample standard deviation

n=16 represent the sample size

Solution to the problem

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 0.90 or 90%, the value of $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

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

$54-1.64\frac{21}{\sqrt{16}}=45.39$

$54 +1.64\frac{21}{\sqrt{16}}=62.61$

So on this case the 90% confidence interval would be given by (45.39;62.61)

4 0

3 years ago