document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=927140>Question 927140</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 19. In 1995, there were 33.8 million cellular subscribers in the U.S.In 1999 there were 86 million.<BR>\n" );
document.write( "a. Let x = 5 represent 1995 and x = 9 represent 1999. Find the average rate of change in the number of subscribers in the US.<BR>\n" );
document.write( "b. Write a linear function that models the number of cellular subscribers in the US.<BR>\n" );
document.write( "c. Interpret the average rate of change and the y-intercept using a complete sentence and be specific to this problem.<BR>\n" );
document.write( "d. According to your calculations, how many cellular subscribers will there be in2012?<BR>\n" );
document.write( "e. Is this a good estimation? Why or why not.<BR>\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 #562747 by </B><A HREF=/tutors/aboutme.mpl?userid=ewatrrr><B>ewatrrr(24785)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ewatrrr><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=ewatrrr><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=562747\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> (9, 86 )<BR>\n" );
document.write( "(5, 33.8) rate of change = m = 52.2/4 = 13.05<BR>\n" );
document.write( ".........<BR>\n" );
document.write( "y -86 = 13.05(x - 9)<BR>\n" );
document.write( "y = 13.05x -31.45<BR>\n" );
document.write( "..........<BR>\n" );
document.write( "rate of growth is ~13M /year since the 1990 total of 31.45M<BR>\n" );
document.write( "........<BR>\n" );
document.write( "x = 12<BR>\n" );
document.write( "y = 13.05(12) - 31.45 = 125.15 million<BR>\n" );
document.write( "assuming rate of growth remains stable, Yes. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );