document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=211350>Question 211350</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Here is the question. Find k if the lines 3x-y=9 and kx+3y=5 are perpendicular. I arranged both equations to equal y; y=3x-9 and y=(5-kx)/3, but I don't know where to go from there  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #159711 by </B><A HREF=/tutors/aboutme.mpl?userid=checkley77><B>checkley77(12844)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=checkley77><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=159711\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 3x-y=9 <BR>\n" );
document.write( "-y=-3x+9<BR>\n" );
document.write( "y=3x+9 ( red line)this line has a slope of 3.<BR>\n" );
document.write( "Therefore all perpendicular lines will have a slope=-1/3<BR>\n" );
document.write( "kx+3y=5<BR>\n" );
document.write( "3y=-kx+5<BR>\n" );
document.write( "y=-kx/3+5/3 <BR>\n" );
document.write( "[-k/3=-1/3]<BR>\n" );
document.write( "k=1 ans.<BR>\n" );
document.write( "y=-x/3+5/3 (green line)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+200%2C+200%2C+-10%2C+10%2C+-10%2C+10%2C+3x+%2B9%2C+-x%2F3+%2B5%2F3%29+ ALIGN=MIDDLE  ALT=\"+graph%28+200%2C+200%2C+-10%2C+10%2C+-10%2C+10%2C+3x+%2B9%2C+-x%2F3+%2B5%2F3%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > (graph 200x200 pixels, x from -10 to 10, y from -10 to 10, of TWO functions 3x +9 and -x/3 +5/3).  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );