document.write( "Question 63517: Hi I am having problems with this: Solve the following equation:\r\n" );
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document.write( "3x = 15·4x-2
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Algebra.Com's Answer #44196 by Edwin McCravy(20056)![]() ![]() You can put this solution on YOUR website! Hi I am having problems with this: Solve the following equation:\r\n" ); document.write( "\r\n" ); document.write( "3x = 15·4x-2\r\n" ); document.write( "\r\n" ); document.write( "We need two rules of natural logarithms:\r\n" ); document.write( "\r\n" ); document.write( "(1) ln(AB) = ln(A) + ln(B)\r\n" ); document.write( "\r\n" ); document.write( "(2) ln(AN) = N·ln(A) \r\n" ); document.write( " \r\n" ); document.write( "-------------------------------------\r\n" ); document.write( "\r\n" ); document.write( " 3x = 15·4x-2\r\n" ); document.write( "\r\n" ); document.write( "Take the natural logarithm of both sides:\r\n" ); document.write( "\r\n" ); document.write( " ln(3x) = ln(15·4x-2)\r\n" ); document.write( "\r\n" ); document.write( "Use rule (2) on the left side and rule (1) on\r\n" ); document.write( "the right side:\r\n" ); document.write( "\r\n" ); document.write( " x·ln(3) = ln(15) + ln(4x-2)\r\n" ); document.write( "\r\n" ); document.write( "Use rule (2) on the last term on the right \r\n" ); document.write( "\r\n" ); document.write( " x·ln(3) = ln(15} + (x-2)·ln(4)\r\n" ); document.write( "\r\n" ); document.write( "To make things easier, let\r\n" ); document.write( "A = ln(3), B = ln(15) and C = ln(4)\r\n" ); document.write( "\r\n" ); document.write( " x·A = B + (x-2)·C \r\n" ); document.write( " Ax = B + C(x-2)\r\n" ); document.write( " Ax = B + Cx - 2C\r\n" ); document.write( " Ax - Cx = B - 2C\r\n" ); document.write( " x(A - C) = B - 2C\r\n" ); document.write( " x = (B - 2C)/(A - C)\r\n" ); document.write( "\r\n" ); document.write( "Now replace A by ln(3), B by ln(15), \r\n" ); document.write( "and C by ln(4):\r\n" ); document.write( "\r\n" ); document.write( " x = [ln(15)-2·ln(4)]/[ln(3)-ln(4)]\r\n" ); document.write( "\r\n" ); document.write( "Now get your calculator and get:\r\n" ); document.write( "\r\n" ); document.write( " x = .2243397393\r\n" ); document.write( "\r\n" ); document.write( "Edwin \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " |