document.write( "Question 892535: I have to a system of two equations in two unknowns that I have to solve:\r
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document.write( "1 = C + D
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document.write( "1 = ((1+sqrt(5))/2)*C + ((1-sqrt(5))/2)*D \r
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document.write( "Hope you can help... :) \n" );
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Algebra.Com's Answer #540579 by Theo(13342)![]() ![]() You can put this solution on YOUR website! it's a little complicated in the execution, but you follow the same rules for solving systems of equations as you would for a more normal looking problem.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your solutions are:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "d = (5-sqrt(5))/10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "c = (5+sqrt(5))/10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the execution could get messy so i assigned a = (1+sqrt(5))/2 and i assigned b = (1-sqrt(5))/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "replacing them in the original equation, then the original equation becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1 = c + d \n" ); document.write( "1 = ac + bd\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this is a lot easier on the eyes, at least for a while.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "using the first equation, i solved for c to get c = 1 - d\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i then used 1-d to replace c in the second equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1 = a(1-d) + bd\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplifying this equation got me:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1 = a - ad + bd\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i factored out the d to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1 = a - d(a-b)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i subtracted 1 from both sides of this euation and i added d(a-b) to both sides of this equaiton to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "d(a-b) = a-1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i then divided both sides of this equation by (a-b) to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "d = (a-1) / (a-b)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this is where i substituted (1+sqrt(5)/2 for a and (1-sqrt(5) for b to get me back to my original expressions.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the equation became.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "d = (1+sqrt(5)/2 - 1) / ((1+sqrt(5)/2) + (1-sqrt(5)/2))\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the rest is just brute calculations which i will show you in the picture at the bottom.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the end of it all was that i got c = (5+sqrt(5)/10 and i got d = (5-sqrt(5))/10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i verified that these solutions were good by checking the original equation using my calculator and replacing c and d with their values.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "all is good as far as i can tell.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "once i found d, finding c was easy because c + d = 1 and i could solve for c to get c = 1 - d.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your solutions are what i showed you up top.\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( " \n" ); document.write( " |