document.write( "Question 235314: I am being asked to write an equation of a line perpendicular to the given line. the equation is x -4y =20. I am not sure how to do this. \n" ); document.write( "
Algebra.Com's Answer #173378 by nerdybill(7384)\"\" \"About 
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I am being asked to write an equation of a line perpendicular to the given line. the equation is x -4y =20
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\n" ); document.write( "First, determine the slope of:
\n" ); document.write( "x -4y =20
\n" ); document.write( "Do this by manipulating it so it is in the slope-intercept form:
\n" ); document.write( "y = mx + b
\n" ); document.write( "where
\n" ); document.write( "m is the slope
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\n" ); document.write( "x -4y =20
\n" ); document.write( "-4y = -x + 20
\n" ); document.write( "Dividing both sides by -4:
\n" ); document.write( "y = (1/4)x - 5
\n" ); document.write( "We see that it has a slope of 1/4
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\n" ); document.write( "If a line is perpendicular, the slopes are negative reciprocal:
\n" ); document.write( "If our new slope is m:
\n" ); document.write( "m(1/4) = -1
\n" ); document.write( "m = -4 (our new slope)
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\n" ); document.write( "So, all we need to do is change the slope of:
\n" ); document.write( "y = (1/4)x - 5
\n" ); document.write( "to -4
\n" ); document.write( "y = -4x - 5 (this is what they are looking for)
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