document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1146943>Question 1146943</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The horizontal line y = k intersects the parabola with equation y = 2(x-3)(x-5) at points A and B. If the length of line segment AB is 6, what is th value of k? </SPAN>\n" );
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document.write( "The parabola has zeros at x=3 and x=5, so the axis of symmetry is x=4.<br><BR>\n" );
document.write( "For the length of AB to be 6, the x values of points A and B have to be 3 either side of the axis of symmetry; so the x values of points A and B are 1 and 7.<br><BR>\n" );
document.write( "Substitute either x=1 or x=7 into the equation to find the y value at those points, which is the value of k the question asks for.<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+2%287-3%29%287-5%29+=+2%284%29%282%29+=+16 ALIGN=MIDDLE  ALT=\"y+=+2%287-3%29%287-5%29+=+2%284%29%282%29+=+16\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "ANSWER: k = 16 </SPAN>\n" );
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