VVVVVVVVVVVVVVVVVVVVVVVVVV

How do I work out A & B ?

Sonja [21]

Answer:

see explanation

Step-by-step explanation:

(a)

Given

x² + 5x + 6

Consider the factors of the constant term ( + 6) which sum to give the coefficient of the x- term ( + 5)

The factors are 3 and 2, since

3 × 2 = 6 and 3 + 2 = 5, hence

x² + 5x + 6 = (x + 3)(x + 2) ← in factored form

(b)

To solve

x² + 5x + 6 = 0 ← use the factored form, that is

(x + 3)(x + 2) = 0

Equate each factor to zero and solve for x

x + 3 = 0 ⇒ x = - 3

x + 2 = 0 ⇒ x = - 2

4 0

3 years ago

Read 2 more answers

Solve the system by finding the determinants and using Cramer's Rule: 2x - y = 4 3x + y = 1

Ahat [919]

Answer:

(1, - 2)

Step-by-step explanation:

2x - y = 4

3x + y = 1

A = $\left[\begin{array}{cc}2&-1\\3&1\end{array}\right]$ = 2(1) - 3( - 1) =2 + 3 = 5

$A_{x}$ = $\left[\begin{array}{cc}4&-1\\1&1\end{array}\right]$ = 4(1) - 1(- 1) = 4 + 1 = 5

$A_{y}$ = $\left[\begin{array}{cc}2&4\\3&1\end{array}\right]$ = 2(1) - 4(3) = 2 - 12 = - 10

x = $\frac{A_{x} }{A}$ = 1

y = $\frac{A_{y} }{A}$ = - 2

(1, - 2)

5 0

2 years ago

Majesty Video Production Inc. wants the mean length of its advertisements to be 26 seconds. Assume the distribution of ad length

Paladinen [302]

Answer:

a) By the Central Limit Theorem, approximately normally distributed, with mean 26 and standard error 0.44.

b) s = 0.44

c) 0.84% of the sample means will be greater than 27.05 seconds

d) 98.46% of the sample means will be greater than 25.05 seconds

e) 97.62% of the sample means will be greater than 25.05 but less than 27.05 seconds

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

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.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation(also called standard error) $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this problem, we have that:

$\mu = 26, \sigma = 2, n = 21, s = \frac{2}{\sqrt{21}} = 0.44$

a. What can we say about the shape of the distribution of the sample mean time?

By the Central Limit Theorem, approximately normally distributed, with mean 26 and standard error 0.44.

b. What is the standard error of the mean time? (Round your answer to 2 decimal places)

$s = \frac{2}{\sqrt{21}} = 0.44$

c. What percent of the sample means will be greater than 27.05 seconds?

This is 1 subtracted by the pvalue of Z when X = 27.05. So

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

By the Central Limit Theorem

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

$Z = \frac{27.05 - 26}{0.44}$

$Z = 2.39$

$Z = 2.39$ has a pvalue of 0.9916

1 - 0.9916 = 0.0084

0.84% of the sample means will be greater than 27.05 seconds

d. What percent of the sample means will be greater than 25.05 seconds?

This is 1 subtracted by the pvalue of Z when X = 25.05. So

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

$Z = \frac{25.05 - 26}{0.44}$

$Z = -2.16$

$Z = -2.16$ has a pvalue of 0.0154

1 - 0.0154 = 0.9846

98.46% of the sample means will be greater than 25.05 seconds

e. What percent of the sample means will be greater than 25.05 but less than 27.05 seconds?"

This is the pvalue of Z when X = 27.05 subtracted by the pvalue of Z when X = 25.05.

X = 27.05

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

$Z = \frac{27.05 - 26}{0.44}$

$Z = 2.39$

$Z = 2.39$ has a pvalue of 0.9916

X = 25.05

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

$Z = \frac{25.05 - 26}{0.44}$

$Z = -2.16$

$Z = -2.16$ has a pvalue of 0.0154

0.9916 - 0.0154 = 0.9762

97.62% of the sample means will be greater than 25.05 but less than 27.05 seconds

8 0

3 years ago

What is the radius of a circle whose equation is x 72 y 102 4

almond37 [142]

The circle of the given radius with equation (x-7)²+(y-10)²=4 is 2 units.

<h3>What do we mean by circles?</h3>

A circle is, in the simplest terms, a circular shape without edges or lines.

Its geometric form is that of a closed curve.

If you track a moving point in a plane while keeping a fixed distance from another point, a circle will have a closed shape.

The English word "circle" derives from the Greek word "kirks," which means "hoop" or "ring."

So, the equation for a circle in its standard form is:

(x - h)² + (y - k)² = r²

Where the radius is r and the centroid is (h, k).

The equation is: (x - 7)² + (y - 10)² = 4

This is rewritten as:

(x - 7)² + (y - 10)² = 2²

When compared to the typical form:

(h, k) = (7, 10)

The circle's radius is 2.

Therefore, the circle of the given radius with equation (x-7)²+(y-10)²=4 is 2 units.

Know more about circles here:

brainly.com/question/24375372

#SPJ4

Correct question:
What is the radius of a circle whose equation is (x-7)²+(y-10)²=4?

8 0

1 year ago

Which customary unit would be best to measure the capacity of water in a dolphin tank at an aquarium?

rewona [7]

The best unit to measure the capacity of water, would be gallons

5 0

2 years ago

Read 2 more answers