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3 years ago

U= 2a - 2. solve for a

Mathematics

2 answers:

Sonja [21]3 years ago

8 0

Answer: a = $\frac{u+2}{2}$

We want to isolate a. Add both sides by 2. Then we get u + 2 = 2a. To get just a, we can divide by 2 to get (u+2)/2.

Hope that helped,

-sirswagger21

olga2289 [7]3 years ago

8 0

Hey there! I'm happy to help!

We want to get a on one side of the equation all on its own.

Let's flip the equation around so a ends up on the left. Usually variables are supposed to be on the left.

2a-2=u

We add 2 to both sides.

2a=u+2

We divide both sides by 2.

a=(u+2)/2

We divide both u and 2 by 2 so our answer is completely simplified.

a=1/2u+1.

I hope that this helps! Have a wonderful day! :D

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H e l p please. can't solve

omeli [17]

Answer:

$\frac{1}{2} 3 \\$

Step-by-step explanation:

Your welcome

8 0

3 years ago

Researchers at the National Cancer Institute released the results of a study that investigated the effect of weed-killing herbic

jolli1 [7]

Answer:

The 95% confidence interval for the difference in the proportion of cancer diagnoses between the two groups is (0.3834, 0.5166).

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem and subtraction between normal variables.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

The randomly sampled 400 dogs from homes where an herbicide was used on a regular basis, diagnosing lymphoma in 230 of them.

This means that:

$p_h = \frac{230}{400} = 0.575, s_h = \sqrt{\frac{0.575*0.425}{400}} = 0.0247$

Of 200 dogs randomly sampled from homes where no herbicides were used, only 25 were found to have lymphoma.

This means that:

$p_n = \frac{25}{200} = 0.125, s_n = \sqrt{\frac{0.125*0.875}{200}} = 0.0234$

Distribution of the difference:

$p = p_h - p_n = 0.575 - 0.125 = 0.45$

$s = \sqrt{s_h^2+s_n^2} = \sqrt{0.0247^2 + 0.0234^2} = 0.034$

Confidence interval:

The confidence interval is:

$p \pm zs$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

The lower bound is $0.45 - 1.96(0.034) = 0.3834$

The upper bound is $0.45 + 1.96(0.034) = 0.5166$

The 95% confidence interval for the difference in the proportion of cancer diagnoses between the two groups is (0.3834, 0.5166).

3 0

3 years ago

The triangle below are drawn on 1-cm dot paper. find the perimeter of each triangle

AnnyKZ [126]

There is no triangle below. Try to edit this problem.

4 0

3 years ago

2 (x-3) + 3 = 6x - 5

anygoal [31]

Answer:

x = $\frac{1}{2}$

Step-by-step explanation:

2x-6+3=6x-5

2x-3=6x-5

2x-6x=-5+3

-4x=-2

x=.5or 1/2

5 0

3 years ago

1) Solve the following system of equations algebraically. Give your solution as two

Bad White [126]

For this case we have the following system of equations:

$y = x ^ 2 + 7x + 12\\y = 2x + 8$

Equating both equations we have:

$x ^ 2 + 7x + 12 = 2x + 8\\x ^ 2 + 7x-2x + 12-8 = 0\\x ^ 2 + 5x + 4 = 0$

We must find the solutions, for this we factor. We look for two numbers that, when multiplied, result in 4 and when added, result in 5. These numbers are 4 and 1:

$4 + 1 = 5\\4 * 1 = 4$