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Is each line parallel, perpendicular or neither parallel or nor perpendicular to the line -x+4y=20? Help?!

Is each line parallel, perpendicular or neither parallel or nor perpendicular to the-example-1
User Andy Hume
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1 Answer

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It's best to start by getting your equation into slope intercept form y=mx+b, where m is the slope

Given -x+4y=20, solve for y

4y=x+20

y=(1/4)x+5

If two lines are parallel, they will have the same slope. If two lines are perpendicular, they will have opposite reciprocal slopes (2/3 and -3/2, for example).

Solving for y, the first equation is y=(1/4)x+2. This has the same slope as the given equation, so the two are parallel.

The second equation is y=-4x-1, with -4 being the opposite reciprocal of 1/4. These two are perpendicular.

The third equation has slope -1/4, which is opposite but not the reciprocal, so it falls into the neither category.

The final equation also has slope -4, again the opposite reciprocal of 1/4. This line is perpendicular.

User Sinstein
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