document.write( "Question 1196468: Find k so that the line through (2, -3) and (k,2) is:
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document.write( "a. parallel to 3x+4y=8
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document.write( "b. perpendicular to 2x-3y= -4\r
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document.write( "k=? \n" );
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Algebra.Com's Answer #829305 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Part (a)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's solve the equation for y \n" ); document.write( "3x+4y = 8 \n" ); document.write( "4y = -3x+8 \n" ); document.write( "y = -3x/4+8/4 \n" ); document.write( "y = (-3/4)x+2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This equation is in y = mx+b form \n" ); document.write( "m = -3/4 = slope \n" ); document.write( "b = 2 = y intercept\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Parallel lines have equal slopes, but different y intercepts. \n" ); document.write( "The line through (2,-3) and (k,2) will also have a slope of -3/4\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's set up the slope expression for the line through those two points \n" ); document.write( "m = slope \n" ); document.write( "m = rise/run \n" ); document.write( "m = (y2-y1)/(x2-x1) \n" ); document.write( "m = (2-(-3))/(k-2) \n" ); document.write( "m = (2+3)/(k-2) \n" ); document.write( "m = 5/(k-2)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Set this equal to -3/4 and solve for k \n" ); document.write( "m = 5/(k-2) \n" ); document.write( "-3/4 = 5/(k-2) \n" ); document.write( "-3(k-2) = 4*5 \n" ); document.write( "-3k+6 = 20 \n" ); document.write( "-3k = 20-6 \n" ); document.write( "-3k = 14 \n" ); document.write( "k = -14/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "======================================================================================\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Part (b)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Solve the given equation for y \n" ); document.write( "2x-3y = -4 \n" ); document.write( "-3y = -2x-4 \n" ); document.write( "y = -2x/(-3)-4/(-3) \n" ); document.write( "y = (2/3)x + 4/3 \n" ); document.write( "The slope of this equation is 2/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Flip the fraction and flip the sign to get -3/2 as the perpendicular slope. \n" ); document.write( "The original slope 2/3 and perpendicular slope -3/2 multiply to -1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We'll plug -3/2 into the slope formula we set up in part (a) earlier.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "m = 5/(k-2) \n" ); document.write( "-3/2 = 5/(k-2) \n" ); document.write( "-3(k-2) = 2*5 \n" ); document.write( "-3k+6 = 10 \n" ); document.write( "-3k = 10-6 \n" ); document.write( "-3k = 4 \n" ); document.write( "k = -4/3 \n" ); document.write( " \n" ); document.write( " |