document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=110317>Question 110317</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Melinda's dad is 30 years older than Melinda is now.  Eight years ago, his age was equal to the squaer of Melinda's age then.  How old is Melinda now? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #80370 by </B><A HREF=/tutors/aboutme.mpl?userid=solver91311><B>solver91311(24713)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=solver91311><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=solver91311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=80370\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Dad's age is d, Melinda's age is m.<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=m%2B30 ALIGN=MIDDLE  ALT=\"d=m%2B30\"   DISABLED_style= \"max-width:90%; height:auto;\" > describes the situation now.<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28d-8%29=%28m-8%29%5E2 ALIGN=MIDDLE  ALT=\"%28d-8%29=%28m-8%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > describes the situation 8 years ago.<BR>\n" );
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document.write( "This seems to be a good candidate for solution by substitution, so substitute <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m%2B30 ALIGN=MIDDLE  ALT=\"m%2B30\"   DISABLED_style= \"max-width:90%; height:auto;\" > for <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d ALIGN=MIDDLE  ALT=\"d\"   DISABLED_style= \"max-width:90%; height:auto;\" > in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28d-8%29=%28m-8%29%5E2 ALIGN=MIDDLE  ALT=\"%28d-8%29=%28m-8%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > making:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28m%2B30-8%29=%28m-8%29%5E2 ALIGN=MIDDLE  ALT=\"%28m%2B30-8%29=%28m-8%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > , then simplify.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m%2B22=m%5E2-16m%2B64 ALIGN=MIDDLE  ALT=\"m%2B22=m%5E2-16m%2B64\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m%5E2-16m-m%2B64-22=0 ALIGN=MIDDLE  ALT=\"m%5E2-16m-m%2B64-22=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=m%5E2-17m%2B42=0 ALIGN=MIDDLE  ALT=\"m%5E2-17m%2B42=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Then we factor:<BR>\n" );
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document.write( "Since the sign on the m term is - and the sign on the constant term is +, we know that we are looking for factors of the form <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28m-a%29%28m-b%29 ALIGN=MIDDLE  ALT=\"%28m-a%29%28m-b%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
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document.write( "The prime factors of 42 are 2, 3, and 7.  So, possible values for a and b are 1 and 42, 2 and 21, 3 and 14, and 6 and 7.  Of these possibilities, only 3 and 14 sum to 17, the coefficient on the m term, so our factors must be:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28m-3%29%28m-14%29 ALIGN=MIDDLE  ALT=\"%28m-3%29%28m-14%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
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document.write( "This means that Melinda is either 3 or 14.  But the answer 3 is not possible, because she wouldn't have been born 8 years previously.  Hence, the answer must be 14.<BR>\n" );
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document.write( "Check:<BR>\n" );
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document.write( "Melinda 14, Dad 44.<BR>\n" );
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document.write( "Eight years ago, Melinda 6 and Dad 36, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6%5E2=36 ALIGN=MIDDLE  ALT=\"6%5E2=36\"   DISABLED_style= \"max-width:90%; height:auto;\" >, check.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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