document.write( "Question 216692: find the distance between P(7,-4) and the line with equation x-3y+5=0.round to the nearest tenth \n" ); document.write( "
Algebra.Com's Answer #163600 by ankor@dixie-net.com(22740)\"\" \"About 
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find the distance between P(7,-4) and the line with equation x-3y+5=0.
\n" ); document.write( "round to the nearest tenth
\n" ); document.write( ":
\n" ); document.write( "Find the slope of the given equation
\n" ); document.write( "x - 3y + 5 = 0
\n" ); document.write( "-3y = -x - 5
\n" ); document.write( "Multiply eq by -1 to get rid of all those negatives
\n" ); document.write( "3y = x + 5
\n" ); document.write( "y = \"1%2F3\"x + \"5%2F3\"
\n" ); document.write( ":
\n" ); document.write( "The slope: m1 = \"1%2F3\"
\n" ); document.write( "Find the slope of a line perpendicular (m2) to this equation
\n" ); document.write( "m1 * m2 = -1; the relationship of slopes of perpendicular lines
\n" ); document.write( "\"1%2F3\"m2 = -1
\n" ); document.write( "m2 = -1*3
\n" ); document.write( "m2 = -3
\n" ); document.write( ":
\n" ); document.write( "Find the equation of the perpendicular line that passes thru P(7,-4)
\n" ); document.write( "Use the point/slope formula y - y1 = m(x - x1)
\n" ); document.write( "y -(-4) = -3(x - 7)
\n" ); document.write( "y + 4 = -3x + 21
\n" ); document.write( "y = -3x + 21 - 4
\n" ); document.write( "y = -3x + 17 is the equation of the perpendicular line
\n" ); document.write( ":
\n" ); document.write( "Find the value of x common to both equations
\n" ); document.write( "\"1%2F3\"x + \"5%2F3\" = -3x + 17
\n" ); document.write( "multiply both sides by 3
\n" ); document.write( "x + 5 = -9x + 51
\n" ); document.write( "x + 9x = 51 - 5
\n" ); document.write( "10x = 46
\n" ); document.write( "x = \"46%2F10\"
\n" ); document.write( "x = 4.6
\n" ); document.write( ":
\n" ); document.write( "Find the value for y:
\n" ); document.write( "y = -3(4.6) + 17
\n" ); document.write( "y = -13.8 + 17
\n" ); document.write( "y = +3.2
\n" ); document.write( ":
\n" ); document.write( "Find the distance from points x1 = 7, y1 =-4 and x2 = 4.6, y2 =3.2
\n" ); document.write( "The distance formula d = \"sqrt%28%28x2-x1%29%5E2+%2B+%28y2-y1%29%5E2%29\"
\n" ); document.write( "Using our point values
\n" ); document.write( "d = \"sqrt%28%284.6-7%29%5E2+%2B+%283.2-%28-4%29%29%5E2%29\"
\n" ); document.write( "d = \"sqrt%28%28-2.4%29%5E2+%2B+%287.2%29%5E2%29\"
\n" ); document.write( "d = \"sqrt%285.76+%2B+51.84%29\"
\n" ); document.write( "d = \"sqrt%2857.6%29\"
\n" ); document.write( "d = 7.589 ~ 7.6 dist between P(7,-4) and Eq x - 3y + 5 = 0.
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