document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=377680>Question 377680</A>: <I><SPAN STYLE=\"word-break: break-all;\"> i need help with this problem: This is the model showing the percentage of Americans with heart disease who are \"x\" years old:\r<BR>\n" );
document.write( "\n" );
document.write( "                           90/1+271e^-0.122x<BR>\n" );
document.write( "At what age will the percentage of Americans with heart disease be 70%?<BR>\n" );
document.write( "I'm thinking it works like this:\r<BR>\n" );
document.write( "\n" );
document.write( "                            0.7 = 90/1+271e^-0.122x<BR>\n" );
document.write( "                         ln 0.7= ln (90/1+271e^-0.122x)<BR>\n" );
document.write( "                         NOW I AM STUCK!!!!! WHAT NOW???!!!! THX!!\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #268374 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=268374\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.7+=+90%2F%281%2B271e%5E%28-0.122x%29%29 ALIGN=MIDDLE  ALT=\"0.7+=+90%2F%281%2B271e%5E%28-0.122x%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.7%281%2B271e%5E%28-0.122x%29%29=90 ALIGN=MIDDLE  ALT=\"0.7%281%2B271e%5E%28-0.122x%29%29=90\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.7%2B189.7e%5E%28-0.122x%29=90 ALIGN=MIDDLE  ALT=\"0.7%2B189.7e%5E%28-0.122x%29=90\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=189.7e%5E%28-0.122x%29=89.3 ALIGN=MIDDLE  ALT=\"189.7e%5E%28-0.122x%29=89.3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=e%5E%28-0.122x%29=89.3%2F189.7 ALIGN=MIDDLE  ALT=\"e%5E%28-0.122x%29=89.3%2F189.7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now take the natural log of both sides.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-0.122x=ln%2889.3%2F189.7%29 ALIGN=MIDDLE  ALT=\"-0.122x=ln%2889.3%2F189.7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28x=-%281%2F0.122%29ln%2889.3%2F189.7%29%29 ALIGN=MIDDLE  ALT=\"highlight%28x=-%281%2F0.122%29ln%2889.3%2F189.7%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );