document.write( "Question 77881: 1. Find the length of a shorter leg of a right triangle if the longer leg is 10 miles more than the shorter leg and the hypotemuse is 10 miles less than twice the shorter leg.\r
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document.write( "2. The sum of two numbers is twentyfive and the sum of their square is three hundred and five. Find the number. \n" );
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Algebra.Com's Answer #55990 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! 1. Find the length of a shorter leg of a right triangle 1. Find the length of a shorter leg of a right triangle if the longer leg is 10 miles more than the shorter leg and the hypotenuse is 10 miles less than twice the shorter leg. \n" ); document.write( ": \n" ); document.write( "Using pythag: a^2 + b^2 = c^2 \n" ); document.write( ": \n" ); document.write( "Let x = a: the shorter leg \n" ); document.write( ": \n" ); document.write( "\"longer leg is 10 miles more than the shorter leg\" \n" ); document.write( "b = (x+10) \n" ); document.write( ": \n" ); document.write( "\"the hypotenuse is 10 miles less than twice the shorter leg.\" \n" ); document.write( "c = (2x - 10) \n" ); document.write( ": \n" ); document.write( "a^2 + b^2 = c^2 is: \n" ); document.write( "x^2 + (x+10)^2 = (2x-10)^2 \n" ); document.write( ": \n" ); document.write( "x^2 + (x^2 + 20x + 100) = 4x^2 - 40x + 100 \n" ); document.write( ": \n" ); document.write( "2x^2 + 20x + 100 = 4x^2 - 40x + 100 \n" ); document.write( ": \n" ); document.write( "0 = 4x^2 - 2x^2 - 40x - 20x + 100 - 100 \n" ); document.write( ": \n" ); document.write( "2x^2 - 60x = 0; a simple equation \n" ); document.write( ": \n" ); document.write( "Factors to: \n" ); document.write( "2x(x - 30) = 0 \n" ); document.write( ": \n" ); document.write( "2x = 0 \n" ); document.write( "and \n" ); document.write( "x = 30 the length of the shorter side \n" ); document.write( ": \n" ); document.write( "Check; a^2 + b^2 = c^2: \n" ); document.write( "30^2 + 40^2 = (60-10)^2 \n" ); document.write( "900 + 1600 = 50^2 = 2500 \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "2. \"The sum of two numbers is twenty five\" \n" ); document.write( "x + y = 25 \n" ); document.write( "y = (25 - x) \n" ); document.write( ": \n" ); document.write( "\"the sum of their squares is three hundred and five\" \n" ); document.write( "x^2 + y^2 = 305 \n" ); document.write( ": \n" ); document.write( "Find the number. \n" ); document.write( "Substitute (25-x) for y in the 2nd equation: \n" ); document.write( "x^2 + (25-x)^2 = 305 \n" ); document.write( ": \n" ); document.write( "x^2 + 625 - 50x + x^2 = 305 \n" ); document.write( ": \n" ); document.write( "2x^2 - 50x + 625 - 305 = 0 \n" ); document.write( ": \n" ); document.write( "2x^2 - 50x + 320 = 0 \n" ); document.write( "; \n" ); document.write( "There is no solution: Look at the discriminant of this equation: \n" ); document.write( " -b^2 - 4 * a * c \n" ); document.write( "-50^2 - 4 * 2 * 320 \n" ); document.write( "2500 - 2560 = -60; <0 means x has no real solutions \n" ); document.write( ": \n" ); document.write( "If we graph the two equations: \n" ); document.write( "y = 25-x \n" ); document.write( "y = Sqrt(305 - x^2) \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( "No point of intersection \n" ); document.write( " \n" ); document.write( " |