document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=143894>Question 143894</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In 1991, the life expectancy of males in a certain country was 68.5 years. In 1996 it was 71.1 years. Let E represent life expectancy in year t and let t represent the number of years since 1991.<BR>\n" );
document.write( "The linear function E(t) that fits the data is <BR>\n" );
document.write( "E(t)=?t + ?<BR>\n" );
document.write( "Use the function to predict the life expectancy of males in 2009?<BR>\n" );
document.write( "E(18)=?\r<BR>\n" );
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document.write( "Can someone help me with this one I do not understand. I dont understand the year t and let t represent the number of years. Doesnt t already represent a certain year, then it says it is the number of years since 1991? HELP!!! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #104765 by </B><A HREF=/tutors/aboutme.mpl?userid=oscargut><B>oscargut(2103)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oscargut><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=oscargut><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=104765\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> E(t)=at+b , we have to find a and b (real numbers)<BR>\n" );
document.write( "In 1991, the life expectancy of males in a certain country was 68.5 years.<BR>\n" );
document.write( "t represent the number of years since 1991.<BR>\n" );
document.write( "then E(0)=68.5 then b=68.5<BR>\n" );
document.write( "then<BR>\n" );
document.write( "E(t)=at+68.5<BR>\n" );
document.write( "Using now:In 1996 it was 71.1 years<BR>\n" );
document.write( "E(5)=a5+68.5=71.1 then 5a=2.6 then a=0.52\r<BR>\n" );
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document.write( "then E(t)=0.52t+68.5 </SPAN>\n" );
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