document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1071699>Question 1071699</A>: <I><SPAN STYLE=\"word-break: break-all;\"> When you are 18 years old you have a hair that is 19 centimeters, and your hair grows about 12 centimeters each year. Let H(t) be the length, in centimeters, of that hair t years after age 18. <BR>\n" );
document.write( "a) fine a formula that gives H as a linear function of t <BR>\n" );
document.write( "b) how long will it take for the air to reach a length of 92 centimeters. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #686646 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=686646\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  When you are 18 years old you have a hair that is 19 centimeters, and your hair grows about 12 centimeters each year. Let H(t) be the length, in centimeters, of that hair t years after age 18.<BR>\n" );
document.write( "H(18) = 19<BR>\n" );
document.write( "m = 12<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Form:: H(t) = m*t + b<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve for \"b\"::<BR>\n" );
document.write( "19 = 12*18 + b<BR>\n" );
document.write( "b = -197<BR>\n" );
document.write( "----- <BR>\n" );
document.write( "a) fine a formula that gives H as a linear function of t<BR>\n" );
document.write( "H(t) = 12t - 197<BR>\n" );
document.write( "----- <BR>\n" );
document.write( "b) how long will it take for the air to reach a length of 92 centimeters.<BR>\n" );
document.write( "Solve::<BR>\n" );
document.write( "92 = 12t - 197<BR>\n" );
document.write( "12t = 289<BR>\n" );
document.write( "time = 24 (age at which hair length is 92 cm<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "-------------  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );