document.write( "Question 54932: Please help me wit this problem:
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document.write( "Find the exact solution to the equation 3^x+5=9^x \n" );
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Algebra.Com's Answer #37139 by stanbon(75887)![]() ![]() ![]() You can put this solution on YOUR website! 3^x+5=9^x \n" ); document.write( "Rewrite as: \n" ); document.write( "3^(2x)-3^x-5=0 \n" ); document.write( "Let 3^x be \"w\" \n" ); document.write( "Rewrite the equation in \"w\", as follows: \n" ); document.write( "w^2-w-5=0 \n" ); document.write( "Use the quadratic formula to solve for \"w\", as follows: \n" ); document.write( "w=[1+-sqrt(1+20)]/2 \n" ); document.write( "w=[1+-sqrt(21)]/2 \n" ); document.write( "Convert back to \"x\" notation. \n" ); document.write( "3^x=[1+-sqrt(21)]/2 \n" ); document.write( "Take the log of both sides to get: \n" ); document.write( "x(log 3)=[1+-sqrt(21)]/2 \n" ); document.write( "x=[1+-sqrt(21)/[2log(3)] \n" ); document.write( "Cheers, \n" ); document.write( "Stan H. \n" ); document.write( " \n" ); document.write( " |