document.write( "Question 1103126: This is supposed to be an exponential equation of quadratic type, but I'm just not seeing it:
\n" ); document.write( "2^x-10(2^-x) +3 = 0\r
\n" ); document.write( "\n" ); document.write( "Here's what I did:
\n" ); document.write( "2^x - 20^-x + 3 = 0
\n" ); document.write( "2^x - (20^-1)^x + 3 = 0
\n" ); document.write( "2^x - (1/20)^x +3 = 0
\n" ); document.write( "2^x - (1^x/20^x) +3 = 0\r
\n" ); document.write( "\n" ); document.write( "And now I'm stumped. I really don't know what I'm doing here. Can you help? Thank you. \n" ); document.write( "

Algebra.Com's Answer #717806 by ikleyn(52781) $\"\"$ $\"About$

You can put this solution on YOUR website!
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document.write( "Your equation is\r\n" );
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document.write( " = 0.\r\n" );
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document.write( "It is a quadratic equation (or EQUIVALENT to a quadratic equation) relative to the variable .\r\n" );
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document.write( "To see it CLEARLY, introduce new variable u = .\r\n" );
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document.write( "Then your equation takes the form\r\n" );
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document.write( " = 0.\r\n" );
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document.write( "Multiply by u to rid off the denominator. You will get\r\n" );
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document.write( " = 0,\r\n" );
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document.write( " = 0.\r\n" );
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document.write( "Factor left side\r\n" );
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document.write( "(u+5)*(u-2) = 0\r\n" );
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document.write( "Only postive root works and make sense: u = 2.\r\n" );
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document.write( "It means  = u = 2,  which implies  x = 1.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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\n" ); document.write( "\n" ); document.write( "That's all.\r
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\n" ); document.write( "\n" ); document.write( "Introducing new variable is the STANDARD method of solutions to problems like this.\r
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\n" ); document.write( "See the lesson\r
\n" ); document.write( "\n" ); document.write( " - Solving exponential equations\r
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