document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=315196>Question 315196</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am studying for a final tomorrow, and I am really stuck on questions such as these: The lines 2x - 3y = -15 and 3x + ky = 12 are perpendicular. What is the value of k? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #225499 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=225499\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Since the two lines are perpendicular, their slopes are \"negative reciprocals\".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Begin by putting both equation into the \"slope-intercept\" form:<BR>\n" );
document.write( "2x - 3y = -15<BR>\n" );
document.write( "-3y = -2x-15<BR>\n" );
document.write( "y = (2/3)x+5<BR>\n" );
document.write( ".<BR>\n" );
document.write( "3x + ky = 1<BR>\n" );
document.write( "ky = -3x+1<BR>\n" );
document.write( "y = (-3/k)x + 1/k<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Because the slopes are \"negative reciprocal\" we have the relation:<BR>\n" );
document.write( "(2/3)(-3/k) = -1<BR>\n" );
document.write( "(2/3)(3/k) = 1<BR>\n" );
document.write( "(2)(k) = 1<BR>\n" );
document.write( "2k = 1<BR>\n" );
document.write( "k = 1/2 </SPAN>\n" );
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