document.write( "Question 359558: From the distance from (-4,-1) to the line defined by y=-2x+1. Express as a radical or a number rounded to the nearest hundredth. \n" ); document.write( "
Algebra.Com's Answer #256552 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
1.\"y=-2x%2B1\"
\n" ); document.write( "The closest distance is formed by the line perpendicular to \"y=-2x%2B1\" that goes through the point (-4,-1).
\n" ); document.write( "To find the perpendicular line, use the slope since perpendicular lines have slopes that are negative reciprocals.
\n" ); document.write( "\"m%5B1%5D%2Am%5B2%5D=-1\"
\n" ); document.write( "\"-2%2Am%5B2%5D=-1\"
\n" ); document.write( "\"m%5B2%5D=1%2F2\"
\n" ); document.write( "Now use the point slope form of a line, \"y-y%5Bp%5D=m%28x-x%5Bp%5D%29\"
\n" ); document.write( "\"y-%28-1%29=%281%2F2%29%28x-%28-4%29%29\"
\n" ); document.write( "\"y%2B1=%281%2F2%29%28x%2B4%29\"
\n" ); document.write( "\"2y%2B2=x%2B4\"
\n" ); document.write( "2.\"-x%2B2y=2\"
\n" ); document.write( "Now that you have both lines, find the intersection of the two lines.
\n" ); document.write( "The distance you're after is the distance from point (-4,-1) to the intersection point.
\n" ); document.write( "Substitute eq. 1 into eq. 2 and solve for \"x\".
\n" ); document.write( "\"-x%2B2%28-2x%2B1%29=2\"
\n" ); document.write( "\"-x-4x%2B2=2\"
\n" ); document.write( "\"-5x=0\"
\n" ); document.write( "\"x=0\"
\n" ); document.write( "Then from eq. 1,
\n" ); document.write( "\"y=-2%280%29%2B1\"
\n" ); document.write( "\"y=1\"
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\n" ); document.write( "Now use the distance formula to find the distance from (-4,-1) to (0,1).
\n" ); document.write( "\"D%5E2=%28x%5B2%5D-x%5B1%5D%29%5E2%2B%28y%5B2%5D-y%5B1%5D%29%5E2\"
\n" ); document.write( "\"D%5E2=%280-%28-4%29%29%5E2%2B%281-%28-1%29%29%5E2\"
\n" ); document.write( "\"D%5E2=%284%29%5E2%2B%282%29%5E2\"
\n" ); document.write( "\"D%5E2=20\"
\n" ); document.write( "\"highlight%28D=2%2Asqrt%285%29%29\" or approximately,
\n" ); document.write( "\"D=4.47\"
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