Tìm ma trận nghịch đảo của ma trận A= [tex]\left[\begin{array}{ccc}1&3&6\\1&4&0\\1&5&15\\\end{array}\right] \\[/tex]

Answer:

Hello! answer: x = 16

Step-by-step explanation:

16 × 16 = 256

12 × 12 = 144

256 + 144 = 400

√400 = 20 therefore x = 16 hope that helps!

Answer:

23

Step-by-step explanation:

Answer:

a) cosA=5/13   b) sinA=12/13

Step-by-step explanation:

Look at the needed angle, then use SOHCAHTOA!

Answer:

cos A = 5/13,  sin A = 12/13

Step-by-step explanation:

Watch the picture for help.

sin A = a/c (According to the picture)

cos A = b/c (According to the picture)

Answer:

option D

because every length is one fifth of the corresponding length of the bigger triangle

Answer:

[tex] x_{1} = 3 + \sqrt {6} [/tex]

[tex] x_{2} = 3 - \sqrt {6} [/tex]

Step-by-step explanation:

Given the quadratic equation;

x² - 6x + 3 = 0

To find the roots of the quadratic equation, we would use the quadratic formula;

Note: the standard form of a quadratic equation is ax² + bx + c = 0

a = 1, b = -6 and c = 3

The quadratic equation formula is;

[tex] x = \frac {-b \; \pm \sqrt {b^{2} - 4ac}}{2a} [/tex]

Substituting into the formula, we have;

[tex] x = \frac {-(-6) \; \pm \sqrt {-6^{2} - 4*1*(3)}}{2*1} [/tex]

[tex] x = \frac {6 \pm \sqrt {36 - (12)}}{2} [/tex]

[tex] x = \frac {6 \pm \sqrt {36 - 12}}{2} [/tex]

[tex] x = \frac {6 \pm \sqrt {24}}{2} [/tex]

[tex] x = \frac {6 \pm 2 \sqrt {6}}{2} [/tex]

[tex] x_{1} = \frac {6 + 2 \sqrt {6}}{2} [/tex]

[tex] x_{1} = \frac {6}{2} + \frac {2 \sqrt {6}}{2} [/tex]

[tex] x_{1} = 3 + \sqrt {6} [/tex]

Or

[tex] x_{2} = \frac {6 - 2 \sqrt {6}}{2} [/tex]

[tex] x_{2} = \frac {6}{2} - \frac {2 \sqrt {6}}{2} [/tex]

[tex] x_{2} = 3 - \sqrt {6} [/tex]

Answer:

Infinitely Many Solutions

Step-by-step explanation:

Given

[tex]\left[\begin{array}{cccccc}1&2&3&4&5&6\\7&6&5&4&3&2\\8&8&8&8&8&8\end{array}\right][/tex]

Required

Determine the type of solution

From the matrix, we have:

3 non-zero rows and 5 variables (the last column is the result)

When the number of variables is more than the number of non-zero rows, then such system has infinitely many solutions

i.e.

[tex]Variables > Non\ zero\ rows[/tex]

[tex]5 > 3[/tex]

Answer:

As a statistical tool, a frequency distribution provides a visual representation for the distribution of observations within a particular test. Analysts often use frequency distribution to visualize or illustrate the data collected in a sample.

Answer:

A and E

Step-by-step explanation:

Answer:

D

Step-by-step explanation:

shaped like a cone

Cone = 1/3

v = 1/3 x 3.14 x 2.5^2 x 4.2

v =27.475

The equation should the artist use to calculate the volume of the

cone is, 4. V=1/3π (2.5)²(4.2)

A cone is a three-dimensional geometric object with a smooth, curved top and a flat base. As a cone's height increases, its radius gradually decreases until it reaches a particular point.

The total surface area of a cone is πr(r + l).

The curved surface area is πrl.

Given, An artist is making a sculpture shaped like a cone having a radius of 2.5 inches and a height of 4.2 inches.

We know The volume of a cone is (1/3)πr²h.

Therefore, The volume of the cone would be,

= (1/3)π(2.5)²×4.2 cubic inches.

learn more about cones here :                                      

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Answer:

62 square feet

Step-by-step explanation:

9 x 8 = 72

5 x 2 = 10

72 - 10 = 62

Answer:

David had x amount of M&M's. He then ate 15 of them for snack. Now David only has 35 M&M's left. How many M&M's did David have in the beginning?

Step-by-step explanation:

Answer:

X= 20

Step-by-step explanation:

Hannah has 35 marbles. Hannah gives away 15 marbles. How many marbles does Hannah have left? Solve the equation X- 15=35.

Answer:

i got (-10/7, -44/7)

Answer:

319,770 different task force groups might possibly be formed

Step-by-step explanation:

The order in which the members of the task force are chosen is not important, which means that the combinations formula is used to solve this question.

Combinations formula:

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

In this question:

Groups of 8 from a set of 22. So

[tex]C_{22,8} = \frac{22!}{8!(22-8)!} = 319770[/tex]

319,770 different task force groups might possibly be formed

Answer:

7 DAYS IN A WEEK

Step-by-step explanation:

MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY SUNDA

7 DAYS

Answer:

it depends... What is X in this situation?

Step-by-step explanation:

A week has seven days.

A day has one day..?

I dont know how to help you, Sorry

Answer:

B = 31.6

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

tan B = opp / adj

tan B = 28.2 / 45.8

taking the inverse tan of each side

tan ^ -1 ( tan B) = tan ^-1 (28.2/45.8)

B =31.62145

Rounding to the nearest tenth

B = 31.6

Answer:

(a): The 95% confidence interval is (46.4, 53.6)

(b): The 95% confidence interval is (47.9, 52.1)

(c): Larger sample gives a smaller margin of error.

Step-by-step explanation:

Given

[tex]n = 30[/tex] -- sample size

[tex]\bar x = 50[/tex] -- sample mean

[tex]\sigma = 10[/tex] --- sample standard deviation

Solving (a): The confidence interval of the population mean

Calculate the standard error

[tex]\sigma_x = \frac{\sigma}{\sqrt n}[/tex]

[tex]\sigma_x = \frac{10}{\sqrt {30}}[/tex]

[tex]\sigma_x = \frac{10}{5.478}[/tex]

[tex]\sigma_x = 1.825[/tex]

The 95% confidence interval for the z value is:

[tex]z = 1.960[/tex]

Calculate margin of error (E)

[tex]E = z * \sigma_x[/tex]

[tex]E = 1.960 * 1.825[/tex]

[tex]E = 3.577[/tex]

The confidence bound is:

[tex]Lower = \bar x - E[/tex]

[tex]Lower = 50 - 3.577[/tex]

[tex]Lower = 46.423[/tex]

[tex]Lower = 46.4[/tex] --- approximated

[tex]Upper = \bar x + E[/tex]

[tex]Upper = 50 + 3.577[/tex]

[tex]Upper = 53.577[/tex]

[tex]Upper = 53.6[/tex] --- approximated

So, the 95% confidence interval is (46.4, 53.6)

Solving (b): The confidence interval of the population mean if mean = 90

First, calculate the standard error of the mean

[tex]\sigma_x = \frac{\sigma}{\sqrt n}[/tex]

[tex]\sigma_x = \frac{10}{\sqrt {90}}[/tex]

[tex]\sigma_x = \frac{10}{9.49}[/tex]

[tex]\sigma_x = 1.054[/tex]

The 95% confidence interval for the z value is:

[tex]z = 1.960[/tex]

Calculate margin of error (E)

[tex]E = z * \sigma_x[/tex]

[tex]E = 1.960 * 1.054[/tex]

[tex]E = 2.06584[/tex]

The confidence bound is:

[tex]Lower = \bar x - E[/tex]

[tex]Lower = 50 - 2.06584[/tex]

[tex]Lower = 47.93416[/tex]

[tex]Lower = 47.9[/tex] --- approximated

[tex]Upper = \bar x + E[/tex]

[tex]Upper = 50 + 2.06584[/tex]

[tex]Upper = 52.06584[/tex]

[tex]Upper = 52.1[/tex] --- approximated

So, the 95% confidence interval is (47.9, 52.1)

Solving (c): Effect of larger sample size on margin of error

In (a), we have:

[tex]n = 30[/tex]     [tex]E = 3.577[/tex]

In (b), we have:

[tex]n = 90[/tex]    [tex]E = 2.06584[/tex]

Notice that the margin of error decreases when the sample size increases.

Answer:

Graph B

Step-by-step explanation:

Hope this helps

Answer:

Step-by-step explanation:

y=x^2+x-30

y=x^2-(6-5)x-30

y=x^2-6x+5x-30

y=x(x-6)-5(x-6)

y=(x-5)(x-6)

Answer:

(x+6)(x-5)

Step-by-step explanation:

The product is -30 and the sum is 1.

Factors of -30 are

-1  and 30

-2 and 15

-3 and 10

-5 and 6

-5 + 6 = 1

Answer:

$1000 each month.

Step-by-step explanation:

$1000 because 12 month and 1 month=$1000 the  family have $3000.

Answer:

see below

Step-by-step explanation:

y = x²-8x+ 15

Let x = -2

y = (-2)²-8(-2)+ 15

  = 4 +16 +15

   = 35

Let x = 1

y = (1)²-8(1)+ 15

     1 -8+15

   =8

The vertex is (4,-1)

Answer:

65 miles

Step-by-step explanation:

y=55+0.15x

64.75=55+0.15x

9.75=0.15x

x=9.75/0.15

x=65 miles

Answer:

ANS.1

Freshmen F = 32

Sophomore S = 48

Total students = 80 students

P(F) = Favorables cases/Total cases

   = 32/80

Hope this helps!

Answer:

32/80 or 2/5 simplified

Step-by-step explanation:

P(Freshman) = 32/80 or 2/5 simplified

Cora, her sister, and four friends. So there are 6 people, 120 candies are divided equally in the bag, so each person gets 20 candies

Each person will get 20 candles.

The division is one of the four basic mathematical operations, the other three being addition, subtraction, and multiplication.

Now it is given that,

Number of candles in the bag = 120

Cora, her sister, and four friends are going to share.

So, Number of person = 6

Thus, candles each person gets = Number of candles in the bag / Number of person

⇒ candles each person gets = 120 / 6

⇒ candles each person gets = 20

Thus, each person will get 20 candles.

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There is no solution.

Step-by-step explanation:

Given:

y = 2x + 1

4x - 2y = 4

Substitute y = 2x + 1 into 4x - 2y = 4

4x - 2(2x + 1) = 4

4x - 4x - 2 = 4

0x = 4 + 2

0x = 6

Anything to the multiple of zero is zero. Hence 0x = 0, and 0 ≠ 6

So there is no solution to the equation.

Answer:

The rate of change of volume of the cone with respect to radius is [tex]\frac{2}{3}\pi\times rh\\[/tex].

Step-by-step explanation:

radius of come = r

height of cone = h

Volume of cone

[tex]V = \frac{1}{3}\pi\times r^2 h[/tex]

As the height is constant, the rate of change of volume with respect to radius is given by the derivative of volume with respect to radius.  

[tex]\frac{dV}{dr}=\frac{1}{3}\pi\times {2r}h\\\\\frac{dV}{dr}=\frac{2}{3}\pi\times rh\\\\[/tex]

Answer:

37.1666666667

Step-by-step explanation:

brainiest please

Answer:

A = $29,201.97

A = P + I where

P (principal) = $20,000.00

I (interest) = $9,201.97

Step-by-step explanation:

First, convert R as a percent to r as a decimal

r = R/100

r = 9.5/100

r = 0.095 rate per year,

Then solve the equation for A

A = P(1 + r/n)nt

A = 20,000.00(1 + 0.095/12)(12)(4)

A = 20,000.00(1 + 0.007916667)(48)

A = $29,201.97

Summary:

The total amount accrued, principal plus interest, with compound interest on a principal of $20,000.00 at a rate of 9.5% per year compounded 12 times per year over 4 years is $29,201.97

Answer:                                                                                                                                                      

2                                                                                                                                                       Step-by-step explanation:

in the places there is X you put -3 , -3 squared minus 7 is equal to 9 , 9-7 is equal to 2

Answer:

[tex] \large{ \tt{❃ \: EXPLANATION}} : [/tex]

[tex] \large{ \tt{❁ \: LET'S \: START}} : [/tex]

[tex] \large{ \tt{⋆ \: f( - 3) = {( - 3)}^{2} - 7}}[/tex]

[tex] \large{ \tt{↦ \: f( - 3) = ( - 3) \times ( - 3) - 7}}[/tex]

[tex] \large{ \tt{↦f( - 3) = 9 - 7}}[/tex]

[tex]↦ \large{ \tt{f( - 3) = \boxed{ \tt{2}}}}[/tex]

[tex] \tt{✺ \: COMFORT \: IS \: THE \: ENEMY \: OF \: ACHIEVEMENT\: ♪}[/tex]

♡ Hope I helped! ♕

☃Have a wonderful day / evening ! ☼

# StayInAndExplore ! ☂

▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁

Answer:

The p-value of the test is 0.1314 > 0.05, which means that it cannot be concluded at the .05 level of significance that a lower proportion of men favor stricter gun control than women

Step-by-step explanation:

Before solving the question, we need to understand the central limit theorem, and subtraction of normal variables.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

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

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Test if a lower proportion of men favor stricter gun control than women:

At the null hypothesis, we test if the proportion is the same, that is, the difference of the proportions if 0. So

[tex]H_0: p_M - p_W = 0[/tex]

At the alternative hypothesis, we test if it is less, that is, the subtraction of the proportions is negative. So

[tex]H_1: p_M - p_W < 0[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{s}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, and s is the standard error.

In a recent survey of gun control laws, a random sample of 564 women, 313 favored stricter gun control laws.

This means that:

[tex]p_W = \frac{313}{564} = 0.555[/tex]

[tex]s_W = \sqrt{\frac{0.555*0.445}{564}} = 0.0209[/tex]

In a random sample of 588 men, 307 favored stricter gun control laws.

This means that:

[tex]p_M = \frac{307}{588} = 0.522[/tex]

[tex]s_M = \sqrt{\frac{0.522*0.478}{588}} = 0.0206[/tex]

0 is tested at the null hypothesis:

This means that [tex]\mu = 0[/tex]

From the samples:

[tex]X = p_M - p_W = 0.522 - 0.555 = -0.033[/tex]

[tex]s = \sqrt{s_M^2+s_W^2} = \sqrt{0.0206^2+0.0209^2} = 0.029[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{s}[/tex]

[tex]z = \frac{-0.033 - 0}{0.029}[/tex]

[tex]z = -1.12[/tex]

P-value of the test and decision:

The p-value of the test is the probability of finding a sample proportion difference greater than 0.033, which is the p-value of z = -1.12.

Looking at the z-table, z = -1.12 has a p-value of 0.1314.

The p-value of the test is 0.1314 > 0.05, which means that it cannot be concluded at the .05 level of significance that a lower proportion of men favor stricter gun control than women

Answer:

1979

91%

Step-by-step explanation:

Given the relation :

P = (318t + 6792) / (1.19t + 107.36)

P = % of household with PC

t = years since 2000

1.) We need to find t, when P = 85%

P = 0.85

0.85 = (318t + 6792) / (1.19t + 107.36)

0.85(1.19t + 107.36) = (318t + 6792)

1.0115t + 91.256 = 318t + 6792

Collect like terms :

1.0115t - 318t = 6792 - 91.256

−316.9885t = 6700.744

t = 6700.744 / - 316.9885

t = - 21.138760

t = - 21 years

2000 - 21 years = 1979

Percentage who had computer in 2014

t = 2014 - 2000 = 14

P = (318(14) + 6792) / (1.19(14)+ 107.36)

P = (4452 + 6792) / (16.66 + 107.36)

P = 11244 / 124.02

P = 90.6627

P = approximately 91%