helppp!! 21 - 3y = -18
3x+ y = -5

Answer:

Step-by-step explanation:

Answer:

200 kids and 500 adults

Step-by-step explanation:

x+y=700

7x+10y=6,400

(200,500)

kids=200

adults=500

Answer:

9 =x

Step-by-step explanation:

The angles are vertical angles and vertical angles are equal

56 = 6x+2

Subtract 2 from each side

56-2 = 6x+2-2

54 = 6x

Divide each side by 6

54/6 = 6x/6

9 =x

Answer:

Degree of freedoms F(4,40)

Step-by-step explanation:

Given:

There is a study which is involving 5 different groups that each contains 9 participants (totally 45)

The objective is to calculate the degree of freedoms

Formula used:

Numerator degree of freedom = k-1

denominator degree of freedom=N-K

Solution:

Numerator degree of freedom = k-1

denominator degree of freedom=N-K

Where,

K= number of groups = 5

N= total number of observations

which is given as follows,

N=45

Then,

Numerator degree of freedom = k-1

=5-1

=4

Denominator degree of freedom = N-K

=45-5

=40

Therefore,

Degree of freedoms, F(4,40)

9514 1404 393

Answer:

Step-by-step explanation:

The attached graph shows the various company costs for x number of hours. The graph nearest the x-axis represents the lowest cost.

We can see that cost is lowest using Company A for 2 hours or less, and Company C for 5 hours or more. For times between those, Company B has the lowest charges.

Of course, the equation for charges in each case is the sum of the service fee and the product of hourly charge and number of hours (x).

__

I find the graphing calculator to be the most efficient tool for solving these. The alternative is to compare the equations pairwise to see which gives lower rates. With a little practice, you learn that the "break even hours" will be the difference in service fees divided by the difference in hourly cost.

For example A will cost the same as B when the $20 service fee and the $10/hour cost difference are the same: for 2 hours. A and C will cost the same when the $45 service fee and the $15/hour cost difference are the same, after 3 hours. B and C will cost the same when the $25 difference in service fees and the $5/hour cost difference are the same, after 5 hours.

So B is cheaper above 2 hours, and C is cheaper than that above 5 hours. With no service fee, A is cheaper for small numbers of hours (<2).

Answer:  [tex]_{13} P _{13}[/tex]

Another acceptable answer is 13! where the exclamation mark is needed.

The numeric form is 6,227,020,800 which is a little over 6 billion.

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

Explanation:

Let's lump those four songs together to form a so called "mega song". So we treat those four items as one single item. This is ensure that those songs are played in the order we want. The other songs aren't treated this way.

We start with 16 songs and drop to 16-4 = 12 songs when taking out those four named songs. Then we add 1 to get 12+1 = 13 since we're adding in that "mega song" block.

---------------------------

So to recap so far, we've gone from 16 songs to 13 songs. The goal is to find out how many arrangements of 13 songs are possible. Order matters.

We'll use the nPr permutation function

[tex]_{n} P _{r} = \frac{n!}{(n-r)!}\\\\[/tex]

where in this case n = 13 and r = 13. Your teacher doesn't want you to evaluate this function. You simply need to state the symbolic form. So that's why we go from [tex]_{n} P _{r}[/tex] to [tex]_{13} P _{13}[/tex]

If you wanted to answer this in terms of factorial notation, then you could say this

[tex]_{n} P _{r} = \frac{n!}{(n-r)!}\\\\_{13} P _{13} = \frac{13!}{(13-13)!}\\\\_{13} P _{13} = \frac{13!}{(0)!}\\\\_{13} P _{13} = \frac{13!}{1}\\\\_{13} P _{13} = 13!\\\\[/tex]

So we can see that the notations [tex]_{13} P _{13}[/tex] and [tex]13![/tex] mean the exact same thing.

If you wanted to know the actual number of permutations, then,

13! = 13*12*11*10*9*8*7*6*5*4*3*2*1 = 6,227,020,800

which is a little over 6 billion permutations.

9514 1404 393

Answer:

  P(x) = x³ -5x² +12x -8

Step-by-step explanation:

If the coefficients are real, then the complex roots must be conjugates. The third root is 2+2i. For root r, (x -r) is a factor, so the factorization is ...

  P(x) = (x -1)(x -2 +2i)(x -2 -2i) = (x -1)((x -2)² +4) = (x -1)(x^2 -4x +8)

Expanding further, we find ...

  P(x) = x³ -5x² +12x -8

Answer:

Step-by-step explanation:

Answer: Yes it is a function.

This is because any x input leads to exactly one y output.

The graph passes the vertical line test. It is impossible to draw a single vertical line through more than one point on the parabolic curve.

Answer:

(x-4) (x-5)

Step-by-step explanation:

* means multiply

first you figure out what 2 numbers

when added make 9

when multiplied make 20

those are 4 and 5

(x  4) (x  5)

in this case

-4 -5 make -9

-4 * -5 make 20

(x-4) (x-5)

Answer:

(x-4)(x-5)

Step-by-step explanation:

Firstly you need to use the second equation formula to get the value of x.

x= [tex]\frac{-(-9)+- \sqrt{(-9)^{2}-4*1*20 } }{2*1}[/tex]

x= [tex]\frac{9+- \sqrt{81-80 } }{2}[/tex]

x= [tex]\frac{9+-1}{2}[/tex]

so,

x=[tex]\frac{9+1}{2}[/tex]      x=5

and

x=[tex]\frac{9-1}{2}[/tex]      x=4

When writing the factor, we have to change signs of 5 and 4. So it will be -5 and -4.

That's why the awnser is (x-4)(x-5)

Hope it helps!

step by step explanation:

[tex]\mathfrak{x}^{2}+{y}^{2}+16=0[/tex]

=[x2+16=0x26]

=[2x{y}^2{16}~0]

=[4×{y}^0{16}]

=[32x{y}^x]

The function has the characteristics is (b) y= (2x^2 - 8) / (x^2 - 9)

The features are given as:

The function that has the above features is (b).

This is proved as follows:

y= (2x^2 - 8) / (x^2 - 9)

Set the denominator not equal to 0, to determine the domain

x^2 - 9 ≠ 0

Add 9 to both sides

x^2 ≠ 9

Take the square roots

x ≠ ±3 --- domain

Replace ≠ with =

x = ±3 --- vertical asymptote

Set the numerator to 0

2x^2 - 8 = 0

Divide through by 2

x^2 - 4 = 0

This gives

x^2 = 4

Take the square roots

x = 2 ---- horizontal asymptote

Hence, the function has the characteristics is (b) y= (2x^2 - 8) / (x^2 - 9)

Read more about functions at:

https://brainly.com/question/4138300

#SPJ1

Answer:

x = 8 minutes

Step-by-step explanation:

Given that,

An internet cafe charges a fixed amount per minute to use the internet.

The cost of using the  internet in dollars is,

[tex]y=\dfrac{3}{4}x[/tex]

Where

x is the number of minutes spent on the internet

We need to find the value of x when y = $6.

So, put y = 6 in the above equation.

[tex]6=\dfrac{3}{4}x\\\\x=\dfrac{6\times 4}{3}\\\\x=8\ min[/tex]

So, 8 minutes must spent on internet.

Answer:

The margin of error for her confdence interval is of 0.3757.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 18 - 1 = 17

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 17 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.99}{2} = 0.995[/tex]. So we have T = 2.8982

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}}[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

Standard deviation of 0.55 meters.

This means that [tex]s = 0.55[/tex]

What is the margin of error for her 99% confidence interval?

[tex]M = T\frac{s}{\sqrt{n}}[/tex]

[tex]M = 2.8982\frac{0.55}{\sqrt{18}}[/tex]

[tex]M = 0.3757[/tex]

The margin of error for her confdence interval is of 0.3757.

Margin of error is the distance between the mean and the limit of confidence intervals. The margin of error for the given condition is 3.28 approximately.

Suppose that we have:

Sample size n  < 30

Then the margin of error(MOE) is obtained as

Margin of Error = [tex]MOE = T_{c}\dfrac{\sigma}{\sqrt{n}}[/tex]

[tex]MOE = T_{c}\dfrac{s}{\sqrt{n}}[/tex]

where [tex]T_{c}[/tex] is critical value of the test statistic at level of significance

For the given case, taking the random variable X to be tracking the height of trees in the sample taken of trees from the considered forest.

Then, by the given data, we get:

[tex]\overline{x} = 4.8[/tex], [tex]s = 4.8[/tex], n = 18

The degree of freedom is n-1 = 17

Level of significance = 100% - 99% = 1% = 0.01

The critical value of t at level of significance 0.01 with degree of freedom 17 is obtained as T = 2.90 (from the t critical values table)

Thus, margin of error for 99% confidence interval for considered case is:

[tex]MOE = T_{c}\dfrac{s}{\sqrt{n}}\\\\MOE = 2.9 \times \dfrac{4.8}{\sqrt{18}} \approx 3.28[/tex]

Thus, the margin of error for the given condition is 3.28 approximately.

Learn more about margin of error here:

https://brainly.com/question/13220147

Answer:

D Is the correct answer Thats was too easy

Answer:

sec(θ) = hypotenuse / adjacent.

Step-by-step explanation:

sec theta= cos -1  theta

Answer:

60 marbles in total

Step-by-step explanation:

Find how many marbles there are in total by dividing 42 by 0.7:

42/0.7

= 60

So, there are 60 marbles in total

Answer:

The volume is maximum when the height is 3 cm.

Step-by-step explanation:

let the side of the removed potion is x.

length of the box = 18 - 2 x

width of the box = 18 - 2 x

height = x

Volume of box

V = Length x width x height

[tex]V = (18 - 2 x)^2 \times x\\\\V = x(324 + 4x^2 - 72 x)\\\\V = 4 x^3 - 72 x^2 + 324 x \\\\\frac{dV}{dx} = 12 x^2 - 144 x + 324 \\\\So,\\\\ \frac{dV}{dx} =0\\\\x^2 - 12 x + 27 = 0 \\\\x^2 -9 x - 3 x + 27 =0\\\\x (x - 9) - 3 (x -9) = 0\\\\x = 3, 9[/tex]

Now

[tex]\frac{d^2V}{dx^2}=24 x - 144 \\\\Put x = 3 \\\\\frac{d^2V}{dx^2}=24\times 3 - 144 = - 72\\\\Put x = 9\\\\\frac{d^2V}{dx^2}=24\times 9 - 144 = 72\\[/tex]

So, the volume is maximum when x = 3 .

Answer:  [tex]y=\frac{1}{4}x-7[/tex]

Step-by-step explanation:

The perpendicular slope of the line(m) = [tex]-\frac{1}{m}[/tex]:

The function formula is y = mx + b, where the y-intercept(b) is found by substituting in the values of a point on the line ⇒ (4, -6):

[tex]y=\frac{1}{4}x+b\\-6=\frac{1}{4}(4)+b\\-6=1+b\\b=-6-1=-7[/tex]

So the perpendicular equation is [tex]y=\frac{1}{4}x-7[/tex].

Answer:

[tex]Z=-2.87[/tex]

Step-by-step explanation:

From the question we are told that:

Probability on women

[tex]P(W)=65 / 500[/tex]

[tex]P(W) = 0.13[/tex]

Probability on women

[tex]P(M)=133 / 700[/tex]

[tex]P(M) = 0.19[/tex]

Confidence Interval [tex]CI=99\%[/tex]

Generally the equation for momentum is mathematically given by

[tex]Z = \frac{( P(W) - P(M) )}{\sqrt{(\frac{ \sigma_1 * \sigma_2 }{(1/n1 + 1/n2)}}})[/tex]

Where

[tex]\sigma_1=(x_1+x_2)(n_1+n_2)[/tex]

[tex]\sigma_1=\frac{( 65 + 133 )}{ ( 500 + 700 )}[/tex]

[tex]\sigma_1=0.165[/tex]

And

[tex]\sigma_2=1 - \sigma = 0.835[/tex]

Therefore

[tex]Z = \frac{( 0.13 - 0.19)}{\sqrt{\frac{( 0.165 * 0.835}{ (500 + 700) )}}}[/tex]

[tex]Z=-2.87[/tex]

9514 1404 393

Answer:

  2

Step-by-step explanation:

In this expression, the terms are the parts of the sum. They are 3x and 4. There are 2 terms.

9514 1404 393

Answer:

  (x, y) = (3/2, -3)

Step-by-step explanation:

Using the second equation, we can write an expression for y:

  y = 3 -4x

Using this in the first equation, we have ...

  -6x -5(3 -4x) = 6

  -6x -15 +20x = 6 . . . . eliminate parentheses

  14x = 21

  x = 21/14 = 1.5

  y = 3 -4(1.5) = 3 -6 = -3

The solution is (x, y) = (1.5, -3).

__

I find a graphing calculator a useful tool for finding solutions quickly.

Answer:

Step-by-step explanation:

multiplication of two rational numbers produce a rational number.

You do X2 + 15 and that will be your answer.

By the way, the 2 is a power and is meant to be smaller on top of the X.

Answer:

Step-by-step explanation:

Total number of balls = 3 + 2 = 5

1)

a)

[tex]Probability \ of \ taking \ 2 \ black \ ball \ with \ replacement\\\\ = \frac{3C_1}{5C_1} \times \frac{3C_1}{5C_1} =\frac{3}{5} \times \frac{3}{5} = \frac{9}{25}\\\\[/tex]

b)

[tex]Probability \ of \ one \ black \ and \ one\ white \ with \ replacement \\\\= \frac{3C_1}{5C_1} \times \frac{2C_1}{5C_1} = \frac{3}{5} \times \frac{2}{5} = \frac{6}{25}[/tex]

c)

Probability of at least one black( means BB or BW or WB)

 [tex]=\frac{3}{5} \times \frac{3}{5} + \frac{3}{5} \times \frac{2}{5} + \frac{2}{5} \times \frac{3}{5} \\\\= \frac{9}{25} + \frac{6}{25} + \frac{6}{25}\\\\= \frac{21}{25}[/tex]

d)

Probability of at most one black ( means WW or WB or BW)

[tex]=\frac{2}{5} \times \frac{2}{5} + \frac{3}{5} \times \frac{2}{5} \times \frac{2}{5} + \frac{3}{5}\\\\= \frac{4}{25} + \frac{6}{25} + \frac{6}{25}\\\\=\frac{16}{25}[/tex]

2)

a) Probability both black without replacement

  [tex]=\frac{3}{5} \times \frac{2}{4}\\\\=\frac{6}{20}\\\\=\frac{3}{10}[/tex]

b) Probability  of one black and one white

 [tex]=\frac{3}{5} \times \frac{2}{4}\\\\=\frac{6}{20}\\\\=\frac{3}{10}[/tex]

c) Probability of at least one black ( BB or BW or WB)

 [tex]=\frac{3}{5} \times \frac{2}{4} + \frac{3}{5} \times \frac{2}{4} + \frac{2}{5} \times \frac{3}{4}\\\\=\frac{6}{20} + \frac{6}{20} + \frac{6}{20} \\\\=\frac{18}{20} \\\\=\frac{9}{10}[/tex]

d) Probability of at most one black ( BW or WW or WB)

 [tex]=\frac{3}{5} \times \frac{2}{4} + \frac{2}{5} \times \frac{1}{4} + \frac{2}{5} \times \frac{3}{4}\\\\=\frac{6}{20} + \frac{2}{20} + \frac{6}{20} \\\\=\frac{14}{20}\\\\=\frac{7}{10}[/tex]

Answer:$36 depending on what question is i just assuming how much she has to pay

Step-by-step explanation:

48 divded by 4 is 12. $48-$12 is $36. The $12 is the 1/4 discount.

Answer:

452.2 cm

Step-by-step explanation:

A = 4πr²

A = 4 (3.14) (6)²

A = 4 (3.14) (36)

A = 452.16

A = 452.2 cm (nearest tenth)

Answer:

0.758

explaination

using poisson distribution

0.08208+0.2052+0.2565+0.2138

0 .758

Answer:

Step-by-step explanation:

50 X 240 = 2700. So you will need 240 packs of 50. They cost 17.95 each, so the multiply. 240 X 17.95 is 4,308. So, 4,308 is your answer.

Answer:

5:8

Step-by-step explanation:

By question it's given that ,

[tex]\implies a:b = 1:2 [/tex]

Let us suppose that the common ratio is x , therefore the Numbers ,

[tex]\implies a = 1x [/tex]

[tex]\implies b = 2x [/tex]

And we need to find the value of ,

[tex]\implies (3a + b): (4a + 2b ) \\\\\implies (3 * x + 2x ) : (4*x + 2*2x ) \\\\\implies (3x + 2x):(4x+4x)\\\\\implies 5x : 8x \\\\\implies 5:8 [/tex]

Hence the required answer is 5:8 .