document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=299886>Question 299886</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Which of the following statements are true ?   \r<BR>\n" );
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document.write( "a. the lines<BR>\n" );
document.write( "    y = 2x - 5,  y = ax + 3<BR>\n" );
document.write( "   are perpendicular when a = -1/2\r<BR>\n" );
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document.write( "b. the lines<BR>\n" );
document.write( "   y = 4x + 3,  y = ax + 2<BR>\n" );
document.write( "   are parallel when a = 4<BR>\n" );
document.write( "  <BR>\n" );
document.write( "c. a vertical line has undefined slope.\r<BR>\n" );
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document.write( "I don't understand how to solve this problem.  Please help. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #215312 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=215312\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Which of the following statements are true ? <BR>\n" );
document.write( "a. the lines<BR>\n" );
document.write( "y = 2x - 5, y = ax + 3<BR>\n" );
document.write( "are perpendicular when a = -1/2<BR>\n" );
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document.write( "The slope of the 1st eqn is +2.  The slope of any line perpendicular is the negative inverse, = -1/2.<BR>\n" );
document.write( "So it's true.<BR>\n" );
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document.write( "b. the lines<BR>\n" );
document.write( "y = 4x + 3, y = ax + 2<BR>\n" );
document.write( "are parallel when a = 4<BR>\n" );
document.write( "The slope of the 1st eqn is +4.  All lines parallel will have the same slope, so it's true.<BR>\n" );
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document.write( "c. a vertical line has undefined slope. <BR>\n" );
document.write( "True.  Parallel to the y-axis is often referred to as vertical.<BR>\n" );
document.write( "Slope = change in y/change in x<BR>\n" );
document.write( "The change in x = 0 --> undefined. </SPAN>\n" );
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