Can you guys helps with these two answers please?

What is the sale price of $7.50 20% off 5.75% tax

V125BC [204]

I think the answer is $5.66

6 0

3 years ago

Read 2 more answers

How many roots does this has?<br>x^2+(2√5x)+2x=-10<br>find Discriminant

Alexxandr [17]

Given:

The equation is

$x^2+(2\sqrt{5})+2x=-10$

To find:

The number of roots and discriminant of the given equation.

Solution:

We have,

$x^2+(2\sqrt{5})x+2x=-10$

The highest degree of given equation is 2. So, the number of roots is also 2.

It can be written as

$x^2+(2\sqrt{5}+2)x+10=0$

Here, $a=1, b=(2\sqrt{5}+2), c=10$ .

Discriminant of the given equation is

$D=b^2-4ac$

$D=(2\sqrt{5}+2)^2-4(1)(10)$

$D=20+8\sqrt{5}+4-40$

$D=8\sqrt{5}-16$

$D\approx 1.89>0$

Since discriminant is $8\sqrt{5}-16\approx 1.89$ , which is greater than 0, therefore, the given equation has two distinct real roots.

3 0

3 years ago

What is the answer to 32.6 - n = 10.2

Alex_Xolod [135]

Answer: 22.4

Step-by-step explanation:

32.6 - 10.2 = 22.4

5 0

3 years ago

A Pew Internet poll asked cell phone owners about how they used their cell phones. One question asked whether or not during the

EastWind [94]

Answer:

a) $\hat p=\frac{471}{1024}=0.460$

The standard error is given by:

$SE= \sqrt{\frac{\hat p(1-\hat p)}{n}}=\sqrt{\frac{0.460(1-0.460)}{1024}}=0.0156$

And the margin of error is given by:

$ME=z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}=1.96\sqrt{\frac{0.460(1-0.460)}{1024}}=0.0305$

b) The 99% confidence interval would be given by (0.429;0.491)

Step-by-step explanation:

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 population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Data given and notation

n=1024 represent the random sample taken

X=471 represent the people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering

$\hat p=\frac{471}{1024}=0.460$ estimated proportion of people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering

p= population proportion of people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering

Part a

The confidence interval would be given by this formula

$\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

For the 95% confidence interval the value of $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$ , with that value we can find the quantile required for the interval in the normal standard distribution.