All categories

3 years ago

How can adding. doubles help you multiply by 2 give an example

1 answer:

3 0

Since you add a number x amount of times by itself when you multiply it by x, we have, for example, 3*2=3+3=6. In addition, 3*3=3+3+3=9 and 3*4=3+3+3+3 (4 times)=12.

You might be interested in

Please answer and explain. 25pts

AVprozaik [17]

C) x<8 and x>10
c) all real Numbers (multiply the -2 to the parenthesis and you get the same equation on both sides which means all real numbers)
C) x is greater than or equal to -3 (solid circle with the line towards positive.)
A) 24 ( distribute then subtract p from both sides)
B) d-12 $\geq$ 51; d $\geq$ 63

7 0

2 years ago

Read 2 more answers

A middle school yearbook committee has 35 members. There are 7 more girls than boys. Write a system of linear equations, define

frez [133]

if the number of boys is x ,then the number of girls is x+7,so 2x+7=35,we can know x=9,so the number of boys is 9,and girls are 16

5 0

2 years ago

What does the solution to an equation with one solution look like?

mihalych1998 [28]

I believe it's b. Hope this helps

3 0

3 years ago

The length of a rectangle is 4 m less than the diagonal and the width is 5 m less than the diagonal. If the area is 82 m^2, how

nikklg [1K]

I hate rounding.

Let's call the diagonal x. It's the hypotenuse of the right triangle whose legs are the rectangle sides.

According to the problem we have a length x-4 and a width x-5 and an area

82 = (x-4)(x-5)

82 = x^2 - 9x + 20

0 = x^2 - 9x - 62

That one doesn't seem to factor so we go to the quadratic formula

$x = \frac 1 2(9 \pm \sqrt{9^2-4(62)}) = \frac 1 2(9 \pm \sqrt{329})$

Only the positive value makes any sense for this problem, so we conclude

$x = \frac 1 2(9 \pm \sqrt{329})$

That's the exact answer. Did I mention I hate rounding? That's about

x = 13.6 meters

Answer: 13.6

----------

It's not clear to me this problem is consistent. By the Pythagorean Theorem the diagonal satisfies

$x^2 = (x-4)^2 + (x-5)^2$

which works out to

$x=9 \pm 2\sqrt{10}$

That's not consistent with the first answer; this problem really has no solution. Tell your teacher to get better material.

5 0

2 years ago

Suppose that a researcher is designing a survey to estimate the proportion of adults in your state who oppose a proposed law tha

irinina [24]

Answer:

$n=\frac{0.5 (1-0.5)}{(\frac{0.02}{1.96})^2}= 2401$

So without prior estimation for the population proportion, using a confidence level of 95% if we want a margin of error about 2% we need al least a sample size of 2401.

Step-by-step explanation:

Previous concepts

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

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

Solution to the problem

The margin of error for the proportion interval is given by this formula:

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

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

The margin of error desired for this case is $ME= \pm 0.02$ equivalent to 2% points

For this case we need to assume a confidence level, let's assume 95%. And since we don't have prior estimation for the population proportion of interest the best value to do an approximation is $\hat p =0.5$

In order to find the critical value we need to take in count that we are finding the margin of error for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.96$

Now we have all the values needed and if we replace into equation (b) we got:

$n=\frac{0.5 (1-0.5)}{(\frac{0.02}{1.96})^2}= 2401$

So without prior estimation for the population proportion, using a confidence level of 95% if we want a margin of error about 2% we need al least a sample size of 2401.

5 0

3 years ago