Find two consecutive whole numbers that 83 lies between.

Which point is a solution to the system of equations graphed below?

UkoKoshka [18]

C.

This is because the x vale is clearly after the 6 and the y value is right on 5

3 0

3 years ago

Let A be a set of numbers.

LUCKY_DIMON [66]

Answer:

a. closed under addition and multiplication

b. not closed under addition but closed under multiplication.

c. not closed under addition and multiplication

d. closed under addition and multiplication

e. not closed under addition but closed under multiplication

Step-by-step explanation:

a.

Let A be a set of all integers divisible by 5.

Let $x,y$ ∈A such that $x=5m\,,\,y=5n$

Find $x+y,xy$

$x+y=5m+5n=5(m+n)$

So, $x+y$ is divisible by 5.

$xy=(5m)(5n)=25mn=5(5mn)$

So,

$xy$ is divisible by 5.

Therefore, A is closed under addition and multiplication.

b.

Let A = { 2n +1 | n ∈ Z}

Let $x,y$ ∈A such that $x=2m+1\,,\,y=2n+1$ where m, n ∈ Z.

Find $x+y,xy$

$x+y=2m+1+2n+1=2m+2n+2=2(m+n+1)$

So,

$x+y$ ∉ A

$xy=(2m+1)(2n+1)=4mn+2m+2n+1=2(2mn+m+n)+1$

So,

$xy$ ∈ A

Therefore, A is not closed under addition but A is closed under multiplication.

c.

$Let A=\{2,5,8,11,14,...\}$

Let $x=2,y=5$ but $x+y=2+5=7$ ∉A

Also,

$xy=2(5)=10$ ∉A

Therefore, A is not closed under addition and multiplication.

d.

Let A = { 17n: n∈Z}

Let $x,y$ ∈ A such that $x=17n,y=17m$

Find x + y and xy

$x+y=17n+17m=17(n+m)$

$xy=(17m)(17n)=289mn=17(17mn)$

So,

$x+y,xy$ ∈ A

Therefore, A is closed under addition and multiplication.

e.

Let A be the set of nonzero real numbers.

Let $x,y$ ∈ A such that $x=-1,y=1$

Find x + y

$x+y=-1+1=0$

So,

$x+y$ ∈ A

Also, if x and y are two nonzero real numbers then xy is also a non-zero real number.

Therefore, A is not closed under addition but A is closed under multiplication.

4 0

2 years ago

At a local university, a sample of 49 evening students was selected in order to determine whether the average age of the evening

pav-90 [236]

Answer:

$z=\frac{23-21}{\frac{3.5}{\sqrt{49}}}=4$

$p_v =2*P(z>4)=0.0000633$

When we compare the significance level $\alpha=0.1$ we see that $p_v$ so we can reject the null hypothesis at 10% of significance. So the the true mean is difference from 21 at this significance level.

Step-by-step explanation:

Data given and notation

$\bar X=23$ represent the sample mean

$\sigma=3.5$ represent the population standard deviation

$n=49$ sample size

$\mu_o =21$ represent the value that we want to test

$\alpha=0.1$ represent the significance level for the hypothesis test.

z would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the average age of the evening students is significantly different from 21, the system of hypothesis would be:

Null hypothesis: $\mu = 21$

Alternative hypothesis: $\mu \neq 21$

The statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{23-21}{\frac{3.5}{\sqrt{49}}}=4$

P-value

Since is a two sided test the p value would be:

$p_v =2*P(z>4)=0.0000633$

Conclusion

When we compare the significance level $\alpha=0.1$ we see that $p_v$ so we can reject the null hypothesis at 10% of significance. So the the true mean is difference from 21 at this significance level.

8 0

3 years ago

Find the equation of the line.<br> Use exact numbers.

Citrus2011 [14]

Answer:

y = 4x + -9

Step-by-step explanation:

The y intercept which is -9, is the point in which the graph crosses the x-axis

In order to find the slope we need to identify two clear points on the graph.

- (0, -9)

- ( 1, -5)

Now that we have our two points we need to find the distance between them.

As you can see on the attachment the distance between the two points is 4 units up and 1 unit to the right, therefore the slope is 4/1 = 4.

Final Answer: y = 4x + -9

3 0

2 years ago

Which equation is related equation to 6d = 108 that isolates the variable

ivann1987 [24]

<span>6d = 108

You would first divide each side by 6 to isolate the variable.
6d = 108
6 6
d = 18

-Gives you thumbs up- </span>

7 0

3 years ago

Read 2 more answers