document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=187584>Question 187584</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780073533490/algebrahomeworkh>Elementary and Intermediate Algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> I have seen this problem on here but I am not understanding why they use zero for \"n\" also I do not understand how to graph this. \r<BR>\n" );
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document.write( "Dental Services:  The national cost C in billions of dollars for dental services can be modeled by the linear equation C = 2.85n + 30.52, when n is the number of years since 1990.<BR>\n" );
document.write( "(a) Find and interpret the C-intercept for the line.\r<BR>\n" );
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document.write( "(b) Find and interpret the n-intercept for the line.<BR>\n" );
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document.write( "(c) Graph the line for n ranging from 0 through 20.<BR>\n" );
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document.write( "(d) If this trend continues, then in what year will the cost of dental services reach 100 billion?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #140594 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=140594\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I have seen this problem on here but I am not understanding why they use zero for \"n\" also I do not understand how to graph this.<BR>\n" );
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document.write( "n=0 represents the number of years after 1990 when the year IS 1990.<BR>\n" );
document.write( "So n=0 IS the year 1990<BR>\n" );
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document.write( "Dental Services: The national cost C in billions of dollars for dental services can be modeled by the linear equation C = 2.85n + 30.52, when n is the number of years since 1990.<BR>\n" );
document.write( "(a) Find and interpret the C-intercept for the line.<BR>\n" );
document.write( "Let n=0, then C(0) = 2.85*0 + 30.52 = 30.52<BR>\n" );
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document.write( "(b) Find and interpret the n-intercept for the line.<BR>\n" );
document.write( "Let C = 0 and solve for \"n\":<BR>\n" );
document.write( "2.85n + 30.52 = 0<BR>\n" );
document.write( "2.85n = -30.52<BR>\n" );
document.write( "n = -10.708<BR>\n" );
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document.write( "(c) Graph the line for n ranging from 0 through 20.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28400%2C300%2C-5%2C35%2C-10%2C120%2C2.85x+%2B+30.52%29 ALIGN=MIDDLE  ALT=\"graph%28400%2C300%2C-5%2C35%2C-10%2C120%2C2.85x+%2B+30.52%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "(d) If this trend continues, then in what year will the cost of dental services reach 100 billion?<BR>\n" );
document.write( "2.85n + 30.52 = 100<BR>\n" );
document.write( "2.85n = 69.48<BR>\n" );
document.write( "n = 24.3789<BR>\n" );
document.write( "Year: 1990+24.3789 = 2014.3789<BR>\n" );
document.write( "Rounding up the year is 2015.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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