6. If b>6, then 3b + 3 could be A. 18 B. 19 C. 20 D. 21 E. 22

If the system below were written as a matrix equation, by which matrix could you multiply both sides to obtain a solution?

ludmilkaskok [199]

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.

Below are the choices:

A.
[8 -6] 
[-5 4] 
B. 
[4 -3] 
[-2.5 2] 
C. 
[-4 5] 
[6 -8] 
D. 
[-2 2.5] 
[3 -4]

B because it is the inverse of
(4 6) 
(5 8) 

Check 
(4.0 -3)(4 6) = (1 0) 
(-2.5 2)(5 8) = (0 1)

3 0

2 years ago

Can someone help me with this pls?

madam [21]

Please bare with me bc I’m bad at wording things, change it as you please!

It’s a minimum. I know that the function is a minimum because whenever there is a - in the beginning of the equation it flips your parabola over the x axis and my parabola becomes concave down. When my parabola is concave up I have a minimum, vise versa is a maximum. Because there isn’t a -, my parabola is concave up meaning the function has a minimum

6 0

2 years ago

Use the net to find the surface area of the regular pyramid

Alja [10]

Answer:

151.9 if the side length of the pentagon/ base of each triangle is 6 m

Step-by-step explanation:

if the side length of the pentagon/ base of each triangle is 6 m then it is a pretty simple question, we just need to add the surface area of the base pentagon and each triangle.

We have the area of the base, so we just need the triangles. The area of a triangle is .5bh, where the base of a triangle here is one side of the pentagon and the height is that indicated red 6. so that means one triangle has an area of .5*6*6 or 18. There are 5 triangles total so that means that with all the triangles there is an area of 90. Adding that to 61.9 gets us 151.9. let me know if you need any more help.

8 0

2 years ago

The following data lists the ages of a random selection of actresses when they won an award in the category of Best Actress, al

Valentin [98]

Answer:

a) $p_v =P(t_{(9)}$

The p value is higher than the significance level given 0.01, so then we can conclude that we FAIL to reject the null hypothesis. And we can say that the true difference for Best Actresses is not significantly lower than the mean for Best Actors at 1% of significance.

b) The 99% confidence interval would be given by (-21.469;2.069)

c) We got the same conclusion as part a, sicne the confidence interval contains the value 0, we FAIL to reject the null hypothesis that the difference between the two

Step-by-step explanation:

Part a

Let put some notation

x=actor's age , y = actress's age

x: 58 41 36 36 34 33 48 37 37 43

y: 26 27 34 26 35 29 23 42 30 34

The system of hypothesis for this case are:

Null hypothesis: $\mu_y- \mu_x \geq 0$

Alternative hypothesis: $\mu_y -\mu_x$

The first step is calculate the difference $d_i=y_i-x_i$ and we obtain this:

d: -32, -14, -2, -10, 1, -4, -25, 5, -7, -9

The second step is calculate the mean difference

$\bar d= \frac{\sum_{i=1}^n d_i}{n}= -9.7$

The third step would be calculate the standard deviation for the differences, and we got:

$s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1} =11.451$

The 4 step is calculate the statistic given by :

$t=\frac{\bar d -0}{\frac{s_d}{\sqrt{n}}}=\frac{-9.7 -0}{\frac{11.451}{\sqrt{10}}}=-2.679$

The next step is calculate the degrees of freedom given by:

$df=n-1=10-1=9$

Now we can calculate the p value, since we have a left tailed test the p value is given by:

$p_v =P(t_{(9)}$

The p value is higher than the significance level given 0.01, so then we can conclude that we FAIL to reject the null hypothesis. And we can say that the true difference for Best Actresses is not significantly lower than the mean for Best Actors at 1% of significance.

Part b

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 means 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.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The confidence interval for the mean is given by the following formula:

$\bar d \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,9)".And we see that $t_{\alpha/2}=3.25$

Now we have everything in order to replace into formula (1):

$-9.7-3.25\frac{11.451}{\sqrt{10}}=-21.469$

$-9.7+3.25\frac{11.451}{\sqrt{10}}=2.069$

So on this case the 99% confidence interval would be given by (-21.469;2.069)

Part c

We got the same conclusion as part a, sicne the confidence interval contains the value 0, we FAIL to reject the null hypothesis that the difference between the two means is 0.

8 0

2 years ago

The radius of a circle measures 15 feet. what is the circumference?

harina [27]

The circumference of this circle is c=94.25ft

7 0

3 years ago