document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=180326>Question 180326</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can you please help me solve this problem?!!?  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9x%5E4=25x%5E2-16 ALIGN=MIDDLE  ALT=\"9x%5E4=25x%5E2-16\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The directions say:  solve the equation by making the appropriate substitution.<BR>\n" );
document.write( "Here is what I have so far....but I am stuck.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9x%5E4-25x%5E2%2B16=0 ALIGN=MIDDLE  ALT=\"9x%5E4-25x%5E2%2B16=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%283x%5E2%29%5E2-25x%5E2%2B16=0 ALIGN=MIDDLE  ALT=\"%283x%5E2%29%5E2-25x%5E2%2B16=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3u%5E2-25u%2B16=0 ALIGN=MIDDLE  ALT=\"3u%5E2-25u%2B16=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "At this point I wasn't sure.  Do I use the quadratic formula???  I tried that but just got confused.  Please help.  Thanks. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #135149 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=135149\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9x%5E4-25x%5E2%2B16=0 ALIGN=MIDDLE  ALT=\"9x%5E4-25x%5E2%2B16=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%283x%5E2%29%5E2-25x%5E2%2B16=0 ALIGN=MIDDLE  ALT=\"%283x%5E2%29%5E2-25x%5E2%2B16=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3u%5E2-25u%2B16=0 ALIGN=MIDDLE  ALT=\"3u%5E2-25u%2B16=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Sub u for x^2<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9u%5E2+-+25u+%2B+16+=+0 ALIGN=MIDDLE  ALT=\"9u%5E2+-+25u+%2B+16+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" >  You used 3u for one term, and u for the other.<BR>\n" );
document.write( "You can factor\"<BR>\n" );
document.write( "(9u-16)*(u-1) = 0<BR>\n" );
document.write( "u = 1, u = 16/9<BR>\n" );
document.write( "Then<BR>\n" );
document.write( "x = +1, -1<BR>\n" );
document.write( "x = +4/3, -4/3<BR>\n" );
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document.write( "Another approach is to \"eyeball\" the 9, -25, 16 and spot that +1 and -1 are solutions, factor those out, then you have a quadratic.<BR>\n" );
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