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3 years ago

What are the solutions to the equation 3x2 + 3x +7 = 0?

Mathematics

1 answer:

KATRIN_1 [288]3 years ago

7 0

Answer:

x is equal to 0.94 and -1.94

Step-by-step explanation:

3x² + 3x + 7 = 0

9x² + 9x + 21 = 0

9x² + 9x + 2.25 = 18.75

(3x + 1.5)² = 18.75

3x + 1.5 = ±√18.75

3x = -1.5 ±√18.75

x = (-1.5 ±√18.75) / 3

x = 0.94, -1.94

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Answer:

$p_v =2*P(t_{(35)}$

Step-by-step explanation:

Assuming this info from R

hist(gifted$count)

## Min. 1st Qu. Median Mean 3rd Qu. Max.

## 21.00 28.00 31.00 30.69 34.25 39.00

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Data given and notation

$\bar X=30.69$ represent the mean

$s=4.3149$ represent the sample standard deviation

$n=36$ sample size

$\mu_o =32$ represent the value that we want to test

$\alpha$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is different than 32, the system of hypothesis would be:

Null hypothesis: $\mu = 32$

Alternative hypothesis: $\mu \neq 32$

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$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{30.69-32}{\frac{4.3149}{\sqrt{36}}}=-1.822$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=36-1=35$

Since is a two sided test the p value would be:

$p_v =2*P(t_{(35)}$

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3 years ago

The formula for the surface area of a cylinder is A=2πr(r+h).Find h if A=80π and r=5.

lesya [120]

A=2<span>πr(r+h)
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3 years ago

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2 years ago

What are the solutions to the equation 3x2 + 3x +7 = 0?​

What are the solutions to the equation 3x2 + 3x +7 = 0?