document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=188052>Question 188052</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need help badly!  Can someone help?\r<BR>\n" );
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document.write( "The credit remaining on a phone card (in dollars) is a linear function of the total calling time made with the card (in minutes), as shown in the figure below. The remaining credit after 45 minutes of calls is $22.80 , and the remaining credit after 64  minutes of calls is $19.76 . What is the remaining credit after 73 minutes of calls? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #141025 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=141025\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The credit remaining on a phone card (in dollars) is a linear function of the<BR>\n" );
document.write( "total calling time made with the card (in minutes), as shown in the figure below.<BR>\n" );
document.write( " The remaining credit after 45 minutes of calls is $22.80 , and the remaining<BR>\n" );
document.write( " credit after 64 minutes of calls is $19.76. <BR>\n" );
document.write( "What is the remaining credit after 73 minutes of calls?<BR>\n" );
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document.write( "Not sure what figure you are referring to, write an equation from the given values:<BR>\n" );
document.write( "Assign the values as follows<BR>\n" );
document.write( "x1 = 45; y1 = 22.80<BR>\n" );
document.write( "x2 = 64; y2 = 19.76<BR>\n" );
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document.write( "Find the slope (m) using the formula: m = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28y2-y1%29%2F%28x2-x1%29 ALIGN=MIDDLE  ALT=\"%28y2-y1%29%2F%28x2-x1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "m = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2819.76-22.80%29%2F%2864-45%29 ALIGN=MIDDLE  ALT=\"%2819.76-22.80%29%2F%2864-45%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28-3.04%29%2F%2819%29 ALIGN=MIDDLE  ALT=\"%28-3.04%29%2F%2819%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "m = -.16<BR>\n" );
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document.write( "Write the equation using the point/slope formula: y - y1 = m(x - x1)<BR>\n" );
document.write( "y - 22.80 = -.16(x - 45)<BR>\n" );
document.write( "y - 22.80 = -.16x + 7.2<BR>\n" );
document.write( "y = -.16x + 7.2 + 22.80<BR>\n" );
document.write( "y = -.16x + 30<BR>\n" );
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document.write( "Use this equation to find the credit (y) when minutes (x) = 73<BR>\n" );
document.write( "y = -.16(73) + 30<BR>\n" );
document.write( "y = -11.68 + 30<BR>\n" );
document.write( "y = $18.32; credit after 73 minute of calls<BR>\n" );
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document.write( "That you can also see the original value of the phone card: x=0, y = $30<BR>\n" );
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document.write( "Did this help you understand what's going on here? Any questions </SPAN>\n" );
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