document.write( "Question 222959: how to figure out different lenghts and widths of a rectangle with perimeters of 500 ft and areas of 21,800 square feet \n" ); document.write( "
Algebra.Com's Answer #166821 by Theo(13342)![]() ![]() You can put this solution on YOUR website! Let x = length and let y = width.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Your 2 equations are:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2x + 2y = 500 \n" ); document.write( "xy = 21800\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Solvle for y in both equations to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 250-x \n" ); document.write( "y = 21800/x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Graph these equations to get what is shown below:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The graphs of these 2 equations do not intersect, therefore you do not have a solution that is common to both.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If you solve these two equations simultaneously by substitution, it will lead to an equation of x^2 - 250x + 21800 = 0.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Solve this using the quadratic equation and you will wind up with imaginary roots.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This means there is no solution for x that is real that will satisfy both equations, I believe.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The graph of the two equations bears this out.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I'm not 100% sure that I'm right but it sure looks like that.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I did a test, however, to see what happens if I do get an intersection on the graph.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I doubled the perimeter to 1000.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Your 2 equations would become:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2x + 2y = 1000 \n" ); document.write( "xy = 21800\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Solvle for y in both equations to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 500-x \n" ); document.write( "y = 21800/x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Graph these equations to get what is shown below:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "You do get an intersection now which says there is a solution to this revised equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Solving it algebraically using the quadratic formula does provide real roots to the equation this time.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have a quadratic equation of x^2 - 500x + 21800 = 0 which yields roots of:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 48.25758998 \n" ); document.write( "and: \n" ); document.write( "x = 451.74241\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "When x is 48.25758998, y = 451.74241\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "When x is 451.74241, y = 48.25758998\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2 * x + 2 * y = 1000 which is the perimeter of the revised equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x*y = 48... * 451... = 21800 which is the area of the revised equation.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "My original analysis is proved correct because when I do get an intersection ojn the graph, I have real solutions, which means that there is no solution to the equations you posed originally. Those are:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2x + 2y = 500 \n" ); document.write( "x*y = 21800\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |