document.write( "Question 178276: find the distance from (2,1) to the line defined by y=-2x-5. Express as a radical or a number rounded to the nearest hundredth \n" ); document.write( "
Algebra.Com's Answer #133261 by Alan3354(69443)![]() ![]() You can put this solution on YOUR website! find the distance from (2,1) to the line defined by y=-2x-5. Express as a radical or a number rounded to the nearest hundredth \n" ); document.write( "----------------------------- \n" ); document.write( "Do it like this one. \n" ); document.write( "------------------------ \n" ); document.write( "find the distance from (6,5) to the line defined by y=-2x-8. express as radical or a number rounded to the nearest hundredth \n" ); document.write( "------------------------- \n" ); document.write( "Find the eqn of the line thru (6,5) perpendicular to y=-2x-8. \n" ); document.write( "All lines perpendicular to it have a slope, m, that's the inverse negative. \n" ); document.write( "y = -2x - 8 is in slope-intercept form, and its slope is -2, so we will find a line thru (6,5) with a slope of +1/2. \n" ); document.write( "y - y1 = m*(x - x1) where (x1,y1) is (6,5) \n" ); document.write( "y - 5 = (1/2)*(x - 6) \n" ); document.write( "2y - 10 = x - 6 \n" ); document.write( "2y = x + 4 \n" ); document.write( "---------------- \n" ); document.write( "Solve the pair of eqns by subbing y into 2y = x + 4 \n" ); document.write( "2y = x + 4 \n" ); document.write( "2*(-2x-8) = x+4 \n" ); document.write( "-4x-16 = x+4 \n" ); document.write( "5x = -20 \n" ); document.write( "x = -4 \n" ); document.write( "------------- \n" ); document.write( "y = -2x-8 = -2*(-4)-8 \n" ); document.write( "y = 0 \n" ); document.write( "The lines intersect at (-4,0) \n" ); document.write( "----------------- \n" ); document.write( "Now find the distance from (6,5) to (-4,0) \n" ); document.write( "s = sqrt((diff in y)^2 + (diff in x)^2) \n" ); document.write( "s = sqrt((0-5)^2 + (-4-6)^2) \n" ); document.write( "s = sqrt(25+100) = sqrt(125) \n" ); document.write( "distance =~11.2 units \n" ); document.write( " |