document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=633098>Question 633098</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 	An investment of $25,400 is placed into an account that earns 6.5% interest compounded quarterly.  In how many years will the investment be worth twice the original amount?\r<BR>\n" );
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document.write( "2)	Solve:  log3(x+8) + log3x=2      The 3 are are at the bottom right corner. \r<BR>\n" );
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document.write( "3) log5x-log5(5-2)=log5(4)     The 5 is in the bottom right corner also \r<BR>\n" );
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document.write( "4) 2^3x+1=13.4 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #398750 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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/cgi-bin/show-face.mpl?user=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=398750\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> An investment of $25,400 is placed into an account that earns 6.5% interest<BR>\n" );
document.write( " compounded quarterly. <BR>\n" );
document.write( "In how many years will the investment be worth twice the original amount?<BR>\n" );
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document.write( "How long to double, the amt doesn't matter<BR>\n" );
document.write( "let t = no. of yrs to double<BR>\n" );
document.write( "(1+<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=.065%2F4 ALIGN=MIDDLE  ALT=\".065%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" >)^(4t) = 2<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281.01625%29%5E%284t%29 ALIGN=MIDDLE  ALT=\"%281.01625%29%5E%284t%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 2<BR>\n" );
document.write( "4t = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=log%282%29%2Flog%281.01625%29 ALIGN=MIDDLE  ALT=\"log%282%29%2Flog%281.01625%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "4t = 43 <BR>\n" );
document.write( "t = 43/4<BR>\n" );
document.write( "t = 10.75 yrs to double in value<BR>\n" );
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document.write( "2) Solve: log3(x+8) + log3(x) = 2<BR>\n" );
document.write( "addition of logs is multiply<BR>\n" );
document.write( "log3(x(x+8)) = 2<BR>\n" );
document.write( "exponent of equiv of logs<BR>\n" );
document.write( "x(x+8) = 3^2<BR>\n" );
document.write( "x^2 + 8x = 9<BR>\n" );
document.write( "a quadratic equation<BR>\n" );
document.write( "x^2 + 8x - 9 = 0<BR>\n" );
document.write( "Factors to<BR>\n" );
document.write( "(x+9)(x-1) = 0<BR>\n" );
document.write( "only the positive solution can be used here<BR>\n" );
document.write( "x = 1<BR>\n" );
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document.write( "3) log5(x) - log5(5-2)= log5(4)<BR>\n" );
document.write( "log5(x) - log5(3)= log5(4)<BR>\n" );
document.write( "subtraction of log means divide<BR>\n" );
document.write( "log5<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x%2F3%29 ALIGN=MIDDLE  ALT=\"%28x%2F3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = log5(4)<BR>\n" );
document.write( "eliminate log5 from both sides<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2F3 ALIGN=MIDDLE  ALT=\"x%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 4<BR>\n" );
document.write( "x = 3(4)<BR>\n" );
document.write( "x = 12<BR>\n" );
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document.write( "4) 2^3x+1=13.4<BR>\n" );
document.write( "Assume this is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%5E%28%283x%2B1%29%29 ALIGN=MIDDLE  ALT=\"2%5E%28%283x%2B1%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 13.4<BR>\n" );
document.write( "3x + 1 = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=log%2813.4%29%2Flog%282%29 ALIGN=MIDDLE  ALT=\"log%2813.4%29%2Flog%282%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "3x + 1 = 3.744<BR>\n" );
document.write( "3x = 3.744 - 1<BR>\n" );
document.write( "3x = 2.744<BR>\n" );
document.write( "x = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2.744%2F3 ALIGN=MIDDLE  ALT=\"2.744%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "x = .9147<BR>\n" );
document.write( "Check this on your calc: enter 2^(3(.9147)+1), results: ~13.4 </SPAN>\n" );
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