document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=69345>Question 69345</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi,<BR>\n" );
document.write( "I'm stuck on this equation. Parallelogram ABCD with vertices A=(1,2), B=(3,8), C= (9,0) and D= (x,y). Hint vector AB=vector DC. I'm really stuck and have no idea how to find x and y. Please help. the answer's supposed to be (7,4) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #49351 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=49351\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Parallelogram ABCD with vertices A=(1,2), B=(3,8), C= (9,0) and D= (x,y).<BR>\n" );
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document.write( "Plot the points so you can visualize the position of D(x,y)<BR>\n" );
document.write( "The first thing you should see is that (7,4) cannot be the right answer. <BR>\n" );
document.write( "You need an equation for CD and an equation for BD<BR>\n" );
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document.write( "CD???<BR>\n" );
document.write( "has the same slope as AB which is \"3\"<BR>\n" );
document.write( "CD is the line with slope of 3 and passing through (9,0)<BR>\n" );
document.write( "That equation is y=3x-27<BR>\n" );
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document.write( "BD????<BR>\n" );
document.write( "has the same slope as AC which is -1/4<BR>\n" );
document.write( "BD is the line with slope of 1/4 and passing through (3,8)<BR>\n" );
document.write( "That equation is y=(-1/4)x+(35/4)<BR>\n" );
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document.write( "Setting 3x-27 = (-1/4)x+(35/4)<BR>\n" );
document.write( "solve for x=11<BR>\n" );
document.write( "Solve for y=6<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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