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- Thread starter mhester88
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- Thread starter
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- Mar 1, 2012

- 980

parallel lines have the same slope

- Jan 30, 2018

- 802

Since this was posted 6 months ago:I'm not understanding this question at all and am not sure how to even begin answering this. Any help would be appreciated.

Write the slope-intercept equation of the line that is parallel to -9x-7y=4 and has the same y-intercept as the graph of -5x+11y=-22.

-9x- 7y= 4 is the same as 7y= -9x- 4 or y= (-9/7)x- 4/7. That has slope -9/7. Any line parallel to it has the same slope so can be written y= (-9/7)x+ c for some number c.

The y-intercept of a graph is the point (0, y) where the graph crosses the y-axis. Setting x= 0 in -5x+ 11y= -22, 11y= -22 so y= -2. The y-intercept is (0, -2). Setting x= 0 in y= (-9/7)x+ c, y= c and we want that to be -2.

y= (-9/7)x- 2. If, like me, you don't like fractions, multiply both sides by 7:

7y= -9x- 14.

You could also add 9x to both sides to get the slightly "prettier"

9x+ 7y= -14.