document.write( "Question 66590: Determine which two equations represent perpendicular lines. (a) y=5x-5 (b) y=1/5x+5 (c) y=-1/5x+5 (d) y=1/5x-5. \n" ); document.write( "

Algebra.Com's Answer #47241 by funmath(2933) $\"\"$ $\"About$

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Determine which two equations represent perpendicular lines.
\n" ); document.write( "(a) y=5x-5 (b) y=1/5x+5 (c) y=-1/5x+5 (d) y=1/5x-5
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\n" ); document.write( "(a) and (c) are perpendicular, this is how you can tell:
\n" ); document.write( "These lines are all in slope intercept form, $\"highlight%28y=mx%2Bb%29\"$ , where m=slope and b=y-intercept.
\n" ); document.write( "Perpendicular lines have slopes that are negative reciprocals of each other, that means their slopes have opposite signs and are upside-down. Because of that if you multiply their slopes you get -1
\n" ); document.write( "The slope of (a) is m=5, the slope of (c) is m=-1/5. They are negative reciprocals of each other, $\"5%2A%28-1%2F5%29=-5%2F5=-1\"$
\n" ); document.write( "Happy Calculating!!! \n" ); document.write( "

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