document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=230434>Question 230434</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The profits of a company that produces auto parts can be represented by a linear function. If the company sells 25 parts its profits are $80 and if the company sells 40 parts its profits are $125. Find the number of parts sold if the profits were $305. If the profits were $905. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #170771 by </B><A HREF=/tutors/aboutme.mpl?userid=texttutoring><B>texttutoring(324)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=texttutoring><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=texttutoring><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=170771\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let x=the number of parts sold<BR>\n" );
document.write( "Let y =the profit\r<BR>\n" );
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document.write( "Find the slope of the linear equation by using the slope formula:\r<BR>\n" );
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document.write( "m=(y2-y1)/(x2-x1)\r<BR>\n" );
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document.write( "In this case, y2=$125, y1=$80. x2=40, x1=25.\r<BR>\n" );
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document.write( "m=($125-$80)/40-25= $45/15<BR>\n" );
document.write( "m=$3/part\r<BR>\n" );
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document.write( "We need to find the y-intercept (or b).\r<BR>\n" );
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document.write( "y=mx+b\r<BR>\n" );
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document.write( "I can choose either point (40,125) or (25,80).\r<BR>\n" );
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document.write( "y=mx+b<BR>\n" );
document.write( "125=3*40+b<BR>\n" );
document.write( "125=120+b<BR>\n" );
document.write( "125-120=b<BR>\n" );
document.write( "5=b\r<BR>\n" );
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document.write( "The line's equation is:\r<BR>\n" );
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document.write( "y=3x+5\r<BR>\n" );
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document.write( "If profits are $305:\r<BR>\n" );
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document.write( "305=3x+5<BR>\n" );
document.write( "300=3x<BR>\n" );
document.write( "x=100\r<BR>\n" );
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document.write( "If profits are $305, 100 parts were sold.\r<BR>\n" );
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document.write( "If profits are $905:\r<BR>\n" );
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document.write( "905=3x+5<BR>\n" );
document.write( "900=3x<BR>\n" );
document.write( "x=300\r<BR>\n" );
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document.write( "If profits were $905, 300 parts were sold. </SPAN>\n" );
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