document.write( "Question 917848: 16^x+4^x+1-3=0 \n" ); document.write( "

Algebra.Com's Answer #556824 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
This is a quadratic equation in disguise.
\n" ); document.write( "Use a substitution,
\n" ); document.write( " $\"u=4%5Ex\"$
\n" ); document.write( " $\"u%5E2=%284%5Ex%29%5E2=4%5E%282x%29=16%5Ex\"$
\n" ); document.write( "So then,
\n" ); document.write( " $\"u%5E2%2Bu%2B1-3=0\"$
\n" ); document.write( " $\"u%5E2%2Bu-2=0\"$
\n" ); document.write( " $\"%28u%2B2%29%28u-1%29=0\"$
\n" ); document.write( "Two \"u\" solutions:
\n" ); document.write( " $\"u%2B2=0\"$
\n" ); document.write( " $\"u=-2\"$
\n" ); document.write( " $\"4%5Ex=-2\"$
\n" ); document.write( "No solutions in x here.
\n" ); document.write( " $\"u-1=0\"$
\n" ); document.write( " $\"u=1\"$
\n" ); document.write( " $\"4%5Ex=1\"$
\n" ); document.write( " $\"highlight%28x=0%29\"$
\n" ); document.write( " \n" ); document.write( "

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