HELP ILL GIVE BRAINLIEST

Find the following sums ( for letter C)

anygoal [31]

Each number in the sum is even, so we can remove a factor of 2.

2 + 4 + 6 + 8 + ... + 78 + 80 = 2 (1 + 2 + 3 + 4 + ... + 39 + 40)

Use whatever technique you used in (a) and (b) to compute the sum

1 + 2 + 3 + 4 + ... + 39 + 40

With Gauss's method, for instance, we have

S = 1 + 2 + 3 + ... + 38 + 39 + 40

S = 40 + 39 + 38 + ... + 3 + 2 + 1

2S = (1 + 40) + (2 + 39) + ... + (39 + 2) + (40 + 1) = 40×41

S = 20×21 = 420

Then the sum you want is 2×420 = 840.

6 0

1 year ago

Simplify the following expression:

Salsk061 [2.6K]

Simplification form of the provided expression is -x⁴-2x³+2x+5 option (B) is correct.

<h3>What is an expression?</h3>

It is defined as the combination of constants and variables with mathematical operators.

The options are:

A) -x⁴ - 2x - x + 2

B) -x⁴ - 2x³ + 2x + 5

C) -2x³ + 1

D) -x - 2x² + 2x + 5

We have an expression:

= (x + 3) - [(x + 2)(x³ - 1)]

$\rm =x+3-\left(x+2\right)\left(x^3-1\right)$

$\rm =x+3-x^4+x-2x^3+2$

$\rm =-x^4-2x^3+2x+3+2$

$\rm =-x^4-2x^3+2x+5$

Thus, simplification form of the provided expression is -x⁴-2x³+2x+5 option (B) is correct.

Learn more about the expression here:

brainly.com/question/14083225

#SPJ1

5 0

2 years ago

I need help for number 5

yKpoI14uk [10]

Answer: 1

Step-by-step explanation:

8 0

3 years ago

Deirdre is factoring the polynomial x2 + 2x – 24. Which combination can she use to replace the middle term, 2x?

mafiozo [28]

to replace 2x we need +6x-4x

3 0

3 years ago

Read 2 more answers

An automobile manufacturer has given its van a 59.5 miles/gallon (MPG) rating. An independent testing firm has been contracted t

LekaFEV [45]

Answer:

The pvalue of the test is 0.0124 < 0.1, which means that there is sufficient evidence at the 0.1 level to support the testing firm's claim.

Step-by-step explanation:

An automobile manufacturer has given its van a 59.5 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the actual MPG for this van since it is believed that the van has an incorrect manufacturer's MPG rating:

At the null hypothesis, we test if the mean is the same, that is:

$H_0: \mu = 59.5$

At the alternate hypothesis, we test that it is different, that is:

$H_a: \mu \neq 59.5$

The test statistic is:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

In which X is the sample mean, $\mu$ is the value tested at the null hypothesis, $\sigma$ is the standard deviation and n is the size of the sample.

59.5 is tested at the null hypothesis:

This means that $\mu = 59.5$

After testing 250 vans, they found a mean MPG of 59.2. Assume the population standard deviation is known to be 1.9.

This means that $n = 250, X = 59.2, \sigma = 1.9$

Value of the test statistic:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

$z = \frac{59.2 - 59.5}{\frac{1.9}{\sqrt{250}}}$

$z = -2.5$

Pvalue of the test and decision:

The pvalue of the test is the probability of finding a mean that differs from 59.5 by at least 0.3, which is P(|Z|>-2.5), which is 2 multiplied by the pvalue of Z = -2.5.

Looking at the z-table, Z = -2.5 has a pvalue of 0.0062

2*0.0062 = 0.0124

The pvalue of the test is 0.0124 < 0.1, which means that there is sufficient evidence at the 0.1 level to support the testing firm's claim.

5 0

3 years ago