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2 years ago

How do I solve this

Mathematics

2 answers:

Alina [70]2 years ago

8 0

$\bf \qquad \qquad \textit{sum of a finite geometric sequence} \\\\ S_n=\displaystyle\sum \limits_{i=1}^{n}\ a_1\cdot r^{i-1}\implies S_n=a_1\left( \cfrac{1-r^n}{1-r} \right)\quad \begin{cases} n=n^{th}\ term\\ a_1=\textit{first term's value}\\ r=\textit{common ratio} \end{cases} \\\\[-0.35em] ~\dotfill$

$\bf S_{20}=\displaystyle\sum \limits_{n=1}^{\stackrel{\stackrel{n}{\downarrow }}{20}}~\stackrel{\stackrel{a_1}{\downarrow }}{3}(\stackrel{\stackrel{r}{\downarrow }}{1.5})^{n-1}\implies S_{20}=3\left(\cfrac{1-1.5^{20}}{1-1.5} \right)\implies S_{20}=3\left(\cfrac{1-\stackrel{\approx}{3325.3}}{-0.5} \right) \\\\\\ S_{20}=3\left(\cfrac{-3324.3}{-0.5} \right)\implies S_{20}=3(6648.6)\implies S_{20}=19945.8$

posledela2 years ago

7 0

19945.8 to simplify, the answer is

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Which table shows a proportional relationship between x and y? Plz Help

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Answer:

The proportional table in the attached figure

Step-by-step explanation:

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form $k=\frac{y}{x}$ or $y=kx$

In a proportional relationship the constant of proportionality k is equal to the slope m of the line and the line passes through the origin

Verify each table

Find the value of the constant of proportionality k for each ordered pair of a table.

$k=\frac{y}{x}$

If all the values of k are the same, then the table represent a proportional relationship between x and y

Table 1

For x=1, y=2 ----> $k=\frac{2}{1}=2$

For x=2, y=4 ----> $k=\frac{4}{2}=2$

For x=3, y=8 ----> $k=\frac{8}{3}=2.7$

The values of k are not equal

This table not represent a proportional relationship between x and y

Table 2

For x=0, y=4

The line not passes through the origin

This table not represent a proportional relationship between x and y

Table 3

For x=0, y=0 ----> is OK the line passes though the origin

For x=1, y=1 ----> $k=\frac{1}{1}=1$

For x=2, y=4 ----> $k=\frac{4}{2}=2$

The values of k are not equal

This table not represent a proportional relationship between x and y

Table 4

For x=1, y=4 ----> $k=\frac{4}{1}=4$

For x=2, y=8 ----> $k=\frac{8}{2}=4$

For x=3, y=12 ----> $k=\frac{12}{3}=4$

The values of k are the same

This table represent a proportional relationship between x and y

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3 years ago

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Answer:

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What is the slope of the line that passes through the points (-2,5) and (3,-4) in the standard (x,y) coordinate plane

Scorpion4ik [409]

To find the slope between two coordinates, you use the formula:

m = y2 - y1/x2 - x1

If coordinate A is (-2, 5) and coordinate B is (3, -4), then:

y2 = -4

y1 = 5

x2 = 3

x1 = -2

So, just substitute the points into the formula.

m = -4 - 5/3 - (-2)

m = -9/5

The slope of the line is -9/5.

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2 years ago

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Answer:

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Step-by-step explanation:

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x + (5x-9)

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How do I solve this​

How do I solve this