document.write( "Question 764164: solve for X:
\n" ); document.write( "3^(x-1)+3^(x-2)=81-3^(x+3) \n" ); document.write( "

Algebra.Com's Answer #465357 by lwsshak3(11628) $\"\"$ $\"About$

You can put this solution on YOUR website!
solve for X:
\n" ); document.write( "3^(x-1)+3^(x-2)=81-3^(x+3)
\n" ); document.write( "***
\n" ); document.write( "3^(x-1)+3^(x-2)+3^(x+3)=81
\n" ); document.write( " $\"3%5E%28x-1%29%281%2B3%5E-1%2B3%5E4%29=81\"$
\n" ); document.write( "3^(x-1)(82+1/3)=81
\n" ); document.write( "3^(x-1)(247/3)=81
\n" ); document.write( "3^(x-1)=81*3/247≈0.9838
\n" ); document.write( "take log of both sides
\n" ); document.write( "(x-1)log3=log(0.9838)
\n" ); document.write( "x=(log(0.9938)/log3)+1
\n" ); document.write( "x≈0.9851
\n" ); document.write( "Check:
\n" ); document.write( "3^(x-1)=3^(.9851-1)≈0.9838
\n" ); document.write( "3^(x-2)=3^(.9851-2)≈0.3279
\n" ); document.write( "3^(x+3)=3^(.9851+3)≈79.6858
\n" ); document.write( "0.9838+0.3279+79.6858≈80.9965≈81 \n" ); document.write( "

\n" );