document.write( "Question 1032298: Find all real solutions x to 4^x - 2^x = 56.\r
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Algebra.Com's Answer #646961 by ikleyn(52800) $\"\"$ $\"About$

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document.write( "Answer. x = 3.\r\n" );
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document.write( "Solution\r\n" );
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document.write( "The standard method of solving equations similar to this one, is to introduce the new variable  y = .\r\n" );
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document.write( "Then your original equation becomes \r\n" );
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document.write( " = .\r\n" );
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document.write( "Factor it:\r\n" );
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document.write( "(y-8)*(y+7) = 0.\r\n" );
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document.write( "Only positive root does fit, since y = .\r\n" );
document.write( "So, y = 8.\r\n" );
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document.write( "Thus you have   = 8,  which implies x = 3.\r\n" );
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