document.write( "Question 1136804: Detroit Road starts in the center of the city, and Lorain Road starts 4 miles west of the center of the city. Both roads run southeast. If these roads are put on a coordinate plane with the center of the city at (0, 0), Lorain Road is represented by the equation y=-x-4 and Detroit Road is represented by the equation y=-x. How far away is Lorain Road from Detroit Road?
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Algebra.Com's Answer #754633 by ikleyn(52814) $\"\"$ $\"About$

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document.write( "To answer the question, it is enough to evaluate the distance from the point (0,0) to the line  y = -x - 4.\r\n" );
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document.write( "There is a remarkable formula which ideally suits for this need.\r\n" );
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document.write( "    Let the straight line in a coordinate plane is defined in terms of its linear equation \r\n" );
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document.write( "         a*x + b*y + c = 0,\r\n" );
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document.write( "    where \"a\", \"b\" and \"c\" are real numbers, and let P = (,) be the point in the coordinate plane. \r\n" );
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document.write( "    Then the distance from the point P to the straight line is equal to\r\n" );
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document.write( "        d = .\r\n" );
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document.write( "Regarding this formula, see the lesson\r\n" );
document.write( "    The distance from a point to a straight line in a coordinate plane\r\n" );
document.write( "in this site.\r\n" );
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document.write( "Your equation in general form is  x + y + 4 = 0.\r\n" );
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document.write( "So, your coefficients are a= 1, b= 1, c= 4,   = 0,  = 0.\r\n" );
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document.write( "Substitute this data    into the formula to get the distance under the question\r\n" );
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document.write( "     =  = .\r\n" );
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document.write( "Answer.  The distance under the question is .\r\n" );
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\n" ); document.write( "\n" ); document.write( "Again, the lessons to read on this topic are\r
\n" ); document.write( "\n" ); document.write( "    - The distance from a point to a straight line in a coordinate plane \r
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\n" ); document.write( "\n" ); document.write( "    - Using formula for the distance from a point to a straight line in a plane to solve word problems \r
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