document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=133315>Question 133315</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This questions gives me the jitters...\r<BR>\n" );
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document.write( "Solve using logs:2^2x+4 minus 2^2x =120\r<BR>\n" );
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document.write( "I know the answer but not the steps:( </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #97501 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=97501\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Solve using logs:2^(2x+4) - 2^2x =120 <BR>\n" );
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document.write( "Since 2^(a+b) = 2^a*2^b you get:\r<BR>\n" );
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document.write( "2^2x*2^4 -2^2x = 120<BR>\n" );
document.write( "But 2^4 = 16\r<BR>\n" );
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document.write( "16(2^2x) - 2^2x - 120\r<BR>\n" );
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document.write( "But 16a - a = 15a.<BR>\n" );
document.write( "So you have:<BR>\n" );
document.write( "15*2^2x = 120<BR>\n" );
document.write( "Divide both sides by 15 to get:<BR>\n" );
document.write( "2^2x = 120/15<BR>\n" );
document.write( "2^2x = 80<BR>\n" );
document.write( "2x log2 = log80<BR>\n" );
document.write( "2x = log80/log2<BR>\n" );
document.write( "2x = 6.321928..<BR>\n" );
document.write( "x = 3.160964...<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
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