Solve 2x+y=2x please answer for me

15x+5y=10 <br>5x-7y=12<br><br>solve using elimination

Paul [167]

Point form: (1,-1)
equation form: x = 1, y = -1

8 0

3 years ago

Please help ASAP! Will give BRAINLIEST! Please read the question THEN answer correctly! No guessing.

Vladimir79 [104]

Understand the problem
Gather your resources
Come to an answering
Check your answer and present the solution

3 0

3 years ago

Read 2 more answers

A researcher reports survey results by stating that the standard error of the mean is 25 the population standard deviation is 40

bezimeni [28]

Answer:

a) A sample of 256 was used in this survey.

b) 45.14% probability that the point estimate was within ±15 of the population mean

Step-by-step explanation:

This question is solved using the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

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.

a. How large was the sample used in this survey?

We have that $s = 25, \sigma = 400$ . We want to find n, so:

$s = \frac{\sigma}{\sqrt{n}}$

$25 = \frac{400}{\sqrt{n}}$

$25\sqrt{n} = 400$

$\sqrt{n} = \frac{400}{25}$

$\sqrt{n} = 16$

$(\sqrt{n})^2 = 16^2[tex][tex]n = 256$

A sample of 256 was used in this survey.

b. What is the probability that the point estimate was within ±15 of the population mean?

15 is the bounds with want, 25 is the standard error. So

Z = 15/25 = 0.6 has a pvalue of 0.7257

Z = -15/25 = -0.6 has a pvalue of 0.2743

0.7257 - 0.2743 = 0.4514

45.14% probability that the point estimate was within ±15 of the population mean

3 0

3 years ago

Divide: (-7x+x^2+15)÷(-3+x)

kakasveta [241]

Since the divisor is in the form (x + #) or (x - #), This can be done by synthetic division.
First put the polynomial ion descending order: x^2 - 7x + 15
Take the coefficients of the terms and follow these steps:

3 | 1 -7 15
   3 -12
___________ Bring down the 1, multiply the 3 by the 1 and place under the
   1 -4    3 -7, then add.
   Multiply 3 by -4, place under the 15, then add.
   The bottom row is our answer. Since the problem started with a second power, the answer will start with a first power.
The bottom row are the coefficients of the terms and the last number is the remainder.
x - 4 remainder 3 ALSO WRITTEN x - 4 + 3/(x -3)

3 0

3 years ago

A cube with an edge of length s has a volume of 27 units.<br> What is the length of s?

matrenka [14]

Answer:

s = 3

Step-by-step explanation:

The volume formula for a cube is V = s^3, where “s” is the edge length. Since we know the volume and need to find “s,” we just do the inverse operation for an exponent, which is a radical. The cubed root of 27 is 3, so there’s your answer! Hope this is helpful & accurate. Best wishes.

5 0

3 years ago