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Help with these two question please, I don't understand.

Which is the equation of the line?

A. $x – 2y = 6$

B. $x + 2y = –6$

C. $2x + y = –3$

D. $2x – y = 3$

What is the slope of the line with equation y = –3?

A. –3

B. 3

C. 0

D. The slope is undefined.

  • 0
    What do you understand? That is a line. It consists of a bunch of (x,y) points. The x and y coordinates are related and every x,y pair satisfies a specific equation. Learning he to understand these equations is standard curriculum from any intro algebra course. So the question is, when did you stop understanding the basics and how far back do we need to backpedal to help you? – 2017-02-23

1 Answers 1

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$1.$

$x$ intercept =$6$

$y$ intercept = $-3$

So, coordinate $1=(6,\;0)=(x_1,\;y_1)$

coordinate $2=(0,\;-3)=(x_2,\;y_2)$

$$y-y_1=\bigg(\dfrac{y_2-y_1}{x_2-x_1}\bigg)(x-x_1)$$ $$y-0=\bigg(\dfrac{-3-0}{0-6}\bigg)(x-6)$$ $$y=\dfrac{-3}{-6}(x-6)$$ $$y=\dfrac{1}{2}(x-6)\implies2y=x-6$$ $$\Rightarrow x-2y=6$$

$2.$ In the second problem equation is a horizontal line and slope of horizontal line is always $0$.