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2 years ago

Im getting an answer that i dont know if its correct so pls help me

Mathematics

1 answer:

Dennis_Churaev [7]2 years ago

6 0

$\bf \begin{array}{llll}
18x-y=24&\implies &\quad 18x-y=24\\
9x+4y=-15&\boxed{\times -2}\implies &-18x-8y=30\\
&&--------\\
&&\qquad 0-9y=54
\end{array}\\\\
-----------------------------\\\\
-9y=54\implies y=\cfrac{54}{-9}\implies \boxed{y=-6}
\\\\\\
\textit{now, let's use that "y" in the first equation}
\\\\\\
18x-(-6)=24\implies 18x+6=24\implies 18x=18\implies \boxed{x=1}$

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2 years ago

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Carlota wrote the equation y + 1 = 2 (x - 3) for the line passing through the points (-1, 3) and (2, 9). Explain and correct her

Art [367]

For this case we have the following equation:

$y + 1 = 2 (x - 3)$

That can be rewritten in the form $y = mx + b$

Where:

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So, we have:

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Where:

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Carlota has the following points:

(-1, 3) and (2, 9)

To know if the line $y = 2x-7$ passes through these points, we must replace them in the equation and the equality must be fulfilled. So:

Point (-1, 3):

Substituting:

$3 = 2 (-1) -7\\3 = -2-7$

$3 = -9$ It's false, equality is not met. The point (-1, 3) does not go through the line.

The equation written by Carlota is erroneous, the procedure to follow is:

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$m=\frac{(y2-y1)}{(x2-x1)}$

$m=\frac{(9-3)}{(2-(-1))}$

$m=\frac{6}{3}$

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We observe that the slope found by Carlota is the same. Let's see cut point "b". For this we substitute any of the points given in the equation:

$y = 2x + b$

Substituting (2,9) we have:

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Thus, Carlota's error was at the cut-off point. The correct equation of the line that passes through the given points is $y = 2x + 5$

Answer:

The correct equation of the line that passes through the given points is $y = 2x + 5$

Carlota's mistake was at the cutoff point

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2 years ago

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aleksley [76]

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Step-by-step explanation:

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