document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=109178>Question 109178</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am helping my daughter with her homework and have no idea what I am doing.\r<BR>\n" );
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document.write( "Computer diskette problem:  A computer store sells 10 floppy diskettes for $15, and 30 for $40.  Assume that the number of dollars varies linearly with the number of diskettes.<BR>\n" );
document.write( "a)  Write the particular equation expressing dollars in terms of diskettes.<BR>\n" );
document.write( "b)  Predicit the price for a box of 100.<BR>\n" );
document.write( "c)  State the domain for your variable.<BR>\n" );
document.write( "d)  Sketch and label the graph. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #79621 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=79621\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A computer store sells 10 floppy diskettes for $15, and 30 for $40. Assume that the number of dollars varies linearly with the number of diskettes.<BR>\n" );
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document.write( "a) Write the particular equation expressing dollars in terms of diskettes.<BR>\n" );
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document.write( "Let x = no. of floppies sold<BR>\n" );
document.write( "Let y = cost of the item<BR>\n" );
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document.write( "find the slope of the equation, slope 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( "Using the given data assign as follows:<BR>\n" );
document.write( "x1=10, y1=15; x2=30, y2= 40<BR>\n" );
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document.write( "m = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2840-15%29%2F%2830-10%29 ALIGN=MIDDLE  ALT=\"%2840-15%29%2F%2830-10%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=25%2F10 ALIGN=MIDDLE  ALT=\"25%2F10\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 1.25 is the slope<BR>\n" );
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document.write( "Find equation using the point/slope formula: y - y1 = m(x - x1)<BR>\n" );
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document.write( "y - 15 - 1.25(x - 10)<BR>\n" );
document.write( "y - 15 = 1.25x - 12.5<BR>\n" );
document.write( "y = 1.25x - 12.5 + 15<BR>\n" );
document.write( "y = 1.25x + 2.5; is the equation expressing cost in terms of no. of items<BR>\n" );
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document.write( "b) Predict the price for a box of 100.<BR>\n" );
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document.write( "Substitute 100 for x in the equation we just created:<BR>\n" );
document.write( "y = 1.25(100) + 2.5<BR>\n" );
document.write( "y = 125 + 2.5<BR>\n" );
document.write( "y = $127.5 is the cost of 100 items<BR>\n" );
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document.write( "c) State the domain for your variable.<BR>\n" );
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document.write( "The domain would be all real integers => 1. You can't include 0 because in our<BR>\n" );
document.write( "equation the cost of 0 items is $2.50, hardly reasonable.<BR>\n" );
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document.write( "d) Sketch and label the graph.<BR>\n" );
document.write( "You can plot the points given and draw a straight line thru them, it should look like this: <BR>\n" );
document.write( "y (vertical is cost) and x (horizontal) is no. of items sold<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+300%2C+200%2C+-10%2C+110%2C+-10%2C+140%2C+1.25x%2B2.5%29+ ALIGN=MIDDLE  ALT=\"+graph%28+300%2C+200%2C+-10%2C+110%2C+-10%2C+140%2C+1.25x%2B2.5%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "How about this, you got a handle this now? </SPAN>\n" );
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