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2 years ago

If a(x)=2x-4 and b(x) =x+2, which of the following expressions produces a quadratic function?

Mathematics

1 answer:

ZanzabumX [31]2 years ago

5 0

Answer:

$(ab)(x)$

Step-by-step explanation:

The complete question in the attached figure

we have

$a(x)=2x-4\\b(x)=x+2$

we know that

(ab)(x) is equal to the product of a(x) and b(x)

$(ab)(x)=(2x-4)(x+2)$

Applying distributive property

$(ab)(x)=2x(x)+2x(2)-4(x)-4(2)$

$(ab)(x)=2x^2+4x-4x-8$

$(ab)(x)=2x^2-8$

This is a quadratic equation

The other expressions not produce a quadratic equation

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B) ¿Cuál es la relación entre el diametro y el radio?

kow [346]

Answer:

La circunferencia es una línea curva, y su longitud depende del radio o del diámetro. La relación matemática entre el radio (o diámetro) y la circunferencia se da por la siguiente fórmula: C = 2πr = πD. Donde C es la circunferencia y π=3.14.

Step-by-step explanation:

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2 years ago

Read 2 more answers

The College Boards, which are administered each year to many thousands of high school students, are scored so as to yield a mean

Marysya12 [62]

Answer:

a) 15.87% of the scores are expected to be greater than 600.

b) 2.28% of the scores are expected to be greater than 700.

c) 30.85% of the scores are expected to be less than 450.

d) 53.28% of the scores are expected to be between 450 and 600.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 500, \sigma = 100$

a. Greater than 600

This is 1 subtracted by the pvalue of Z when X = 600. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{600 - 500}{100}$

$Z = 1$

$Z = 1$ has a pvalue of 0.8413.

1 - 0.8413 = 0.1587

15.87% of the scores are expected to be greater than 600.

b. Greater than 700

This is 1 subtracted by the pvalue of Z when X = 700. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{700 - 500}{100}$

$Z = 2$

$Z = 2$ has a pvalue of 0.9772

1 - 0.9772 = 0.0228

2.28% of the scores are expected to be greater than 700.

c. Less than 450

Pvalue of Z when X = 450. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{450 - 500}{100}$

$Z = -0.5$

$Z = -0.5$ has a pvalue of 0.3085.

30.85% of the scores are expected to be less than 450.

d. Between 450 and 600

pvalue of Z when X = 600 subtracted by the pvalue of Z when X = 450. So

X = 600

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{600 - 500}{100}$

$Z = 1$

$Z = 1$ has a pvalue of 0.8413.

X = 450

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{450 - 500}{100}$

$Z = -0.5$

$Z = -0.5$ has a pvalue of 0.3085.

0.8413 - 0.3085 = 0.5328

53.28% of the scores are expected to be between 450 and 600.

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2 years ago

19. Describe the sequence of transformations from quadrilateral WXYZ to W"X"Y"Z"

Tpy6a [65]

Answer:

The sequence is as following:

1. Reflection 180°

2. Reflection over the line x=5

3. Translation 2 units down.

Step-by-step explanation:

The question is as following:

Describe the sequence of transformations from Quadrilateral WXYZ to W”X”Y”Z”.

The picture is a coordinate plane with

W= (-8,8)

X= (-2,8)

Y= (-2,4)

Z= (-8,4)

W”= (2,-10)

X”= (8,-10)

Y”= (8,-6)

Z”= (2,-6)

=================================

See the attached figure

The sequence is:

Reflection 180° ⇒ Reflection over the line x=5 ⇒ translation 2 units down.

Rule of reflection 180° is (x, y) → (–x, –y)

Rule of reflection over the line x=5 is (x, y) → (–x+10 , y)

Rule of translation 2 units down is (x, y) → (x , y–2)

The way of thinking:

1. The rectangle at the second quadrant, we need make it at the fourth quadrant, so, the suitable is Reflection 180°

2. After reflection 180°, it is noticed that we need reverse the vertices so we need to make a reflection over its vertical axis which is at x = 5

3. We need to translate it 2 units down to overlap with the required coordinates.

Check the points:

W(-8,8) ⇒ (8,-8) ⇒ (2,-8) ⇒ (2,-10)⇒W"

X(-2,8) ⇒ (2,-8) ⇒ (8,-8) ⇒ (8,-10)⇒X"

Y(-2,4) ⇒ (2,-4) ⇒ (8,-4) ⇒ (8,-6)⇒Y"

Z(-8,4) ⇒ (8,-4) ⇒ (2,-4) ⇒ (2,-6)⇒Z"

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2 years ago

Hannah’s favorite toy character is sold wearing one of many outfits. An outfit consists of one shirt, one pair of pants, and one

Serggg [28]

There is a 1/6 probability

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2 years ago

A random sample of 20 students yielded a mean of ¯x = 72 and a variance of s2 = 16 for scores on a college placement test in mat

Helen [10]

Answer:

The 98% confidence interval for the variance in the pounds of impurities would be $8.400 \leq \sigma^2 \leq 39.827$ .

Step-by-step explanation:

1) Data given and notation

$s^2 =16$ represent the sample variance

s=4 represent the sample standard deviation

$\bar x$ represent the sample mean

n=20 the sample size

Confidence=98% or 0.98

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 mean or variance 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.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case the sample variance is given and for the sample deviation is just the square root of the sample variance.

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=20-1=19$

Since the Confidence is 0.98 or 98%, the value of $\alpha=0.02$ and $\alpha/2 =0.01$ , and we can use excel, a calculator or a table to find the critical values.