document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=455374>Question 455374</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 3.	The linear equation y=0.16x + 1.22 represents an estimate of the average cost of gas for year x starting in 2003. The year 2004 would be represented by x = 1, for example, as it is the first year in the study. Similarly, 2009 would be year 6, or x = 6.<BR>\n" );
document.write( "1. What year would be represented by x=9?<BR>\n" );
document.write( "2. What x-value represents the year 2020?<BR>\n" );
document.write( "3. What is the slope (or rate of change) of this equation?<BR>\n" );
document.write( "4. What is the y-intercept?<BR>\n" );
document.write( "5. What does the y-intercept represent?<BR>\n" );
document.write( "6. Assuming this growth trned continues, what will the price of gasoline be in the year 2020? How did you arrive at your answer?<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 #312650 by </B><A HREF=/tutors/aboutme.mpl?userid=oberobic><B>oberobic(2304)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oberobic><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=312650\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> y = 0.16x + 1.22<BR>\n" );
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document.write( "<tr><td>x-value<td>Year\r\n" );
document.write( "<tr><td>0<td>2003\r\n" );
document.write( "<tr><td>1<td>2004\r\n" );
document.write( "<tr><td>2<td>2005\r\n" );
document.write( "<tr><td>3<td>2006\r\n" );
document.write( "<tr><td>4<td>2007\r\n" );
document.write( "<tr><td>5<td>2008\r\n" );
document.write( "<tr><td>6<td>2009\r\n" );
document.write( "<tr><td>7<td>2010\r\n" );
document.write( "<tr><td>8<td>2011\r\n" );
document.write( "<tr><td>9<td>2012\r\n" );
document.write( "<tr><td>10<td>2013\r\n" );
document.write( "<tr><td>11<td>2014\r\n" );
document.write( "<tr><td>12<td>2015\r\n" );
document.write( "<tr><td>13<td>2016\r\n" );
document.write( "<tr><td>14<td>2017\r\n" );
document.write( "<tr><td>15<td>2018\r\n" );
document.write( "<tr><td>16<td>2019\r\n" );
document.write( "<tr><td>17<td>2020\r\n" );
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document.write( "</TABLE><BR>\n" );
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document.write( "The given equation is in slope-intercept form, so you can answer a couple of questions by inspection.<BR>\n" );
document.write( "y = 0.16x + 1.22<BR>\n" );
document.write( "slope = 0.16<BR>\n" );
document.write( "y-intercept = 1.22<BR>\n" );
document.write( "That means the price of gas was $1.22 in 2003.<BR>\n" );
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document.write( "x-intercept is where y=0, so we solve<BR>\n" );
document.write( "0 = 0.16x + 1.22<BR>\n" );
document.write( "-.16x = 1.22<BR>\n" );
document.write( "x = 1.22/-.16<BR>\n" );
document.write( "x = -7.625<BR>\n" );
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document.write( "What does this linear model forecast the price of gas in 2020 to be?<BR>\n" );
document.write( "x=17<BR>\n" );
document.write( "y = 0.16*17 + 1.22<BR>\n" );
document.write( "y = 2.72 + 1.22<BR>\n" );
document.write( "y = 3.94<BR>\n" );
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document.write( "Done<BR>\n" );
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document.write( "</TD></TR></TABLE>\n" );