It's easy I'm just not I'm my head rn can someone help?

Calculate the arithmetic sequence in which a9=17 and the common difference is d=-2.1

jek_recluse [69]

Answer:

$S_{31}=71.3$

Step-by-step explanation:

The nth term of an arithmetic sequence is given by the formula,

$U_n=a_1+(n-1)d$

We were given that the 9th term is $17$ .

$\Rightarrow 17=a_1+(9-1)(-2.1)$

$\Rightarrow 17=a_1+(8)\times(-2.1)$

$\Rightarrow 17=a_1-\frac{84}{5}$

$\Rightarrow 17+\frac{84}{5}=a_1$

$\Rightarrow a_1=\frac{169}{5}$

The sum of the first n-terms is given by the formula,

$S_n=\frac{n}{2}(2a_1+(n-1)d)$

To find $S_{31}$ , we substitute $n=31$ , $a_1=\frac{169}{5}$ and $d=-2.1$ .

$\Rightarrow S_{31}=\frac{31}{2}(2(\frac{169}{5}+(31-1)(-2.1))$

$\Rightarrow S_{31}=\frac{31}{2}(2(\frac{169}{5}+(30)(-2.1))$

$\Rightarrow S_{31}=\frac{31}{2}(\frac{23}{5})$

$\Rightarrow S_{31}=\frac{713}{10}$

$\Rightarrow S_{31}=71.3$

The correct answer is D

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the circumference of a circular painting is 40.82 ft. what is the radius of the painting? use 3.14 do not round

diamong [38]

Your answer would be about 20.41

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the builder measures the perimeter of the foundation to be 425 ft. he must order steel beams to install around the perimeter of

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Answer:

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Step-by-step explanation:

I just went on google and typed in "ft. to meters converter".

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What is the pattern of the trend line equation in this graph?

kondaur [170]

The pattern of the trend line from what we can see here shows the existence of a positive upward trend.

<h3>What is a positive upward trend?</h3>

We can see that the graph has fluctuations which have an upward trend over the years. This upward trend can be gotten from the straight line that was drawn on the graph.

It slants to the top. This shows us that the trend is positive and rising over the period of time that we have in the graph. In the graph, the upward trend can be seen from the fact that there has been a rise in the temperature of the city over the time period that was illustrated. The increase in temperature rose from 31.5 to 33 degrees period of time.

Hence we can conclude that The pattern of the trend line from what we can see here shows the existence of a positive upward trend.

Read more on trend lines here: brainly.com/question/27194207

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Ms. Martin bought 96 ounces of decaf coffee beans and 72 ounces of

denis23 [38]

Answer:

its B

Step-by-step explanation:

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