document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=839121>Question 839121</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 2 points are chosen on the parabola defined by y=x^2, one with a positive x-coordinate and the other with a negative x-coordinate. If the points are (a,b) and (c,d), where a < 0 and c > 0, find the y-intercept of the line joining the 2 points in terms of a and c   </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #505538 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=505538\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 2 points are chosen on the parabola defined by y=x^2, one with a positive x-coordinate and the other with a negative x-coordinate. If the points are (a,b) and (c,d), where a < 0 and c > 0, find the y-intercept of the line joining the 2 points in terms of a and c<BR>\n" );
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document.write( "Points: <BR>\n" );
document.write( "(a,b) implies b = a^2 because y = x^2<BR>\n" );
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document.write( "(c,d) implies d = c^2 because y = x^2<BR>\n" );
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document.write( "Using the two points (a,b) and (c,d)<BR>\n" );
document.write( "slope = (d-b)(c-a)<BR>\n" );
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document.write( "Substituting for b and d you get: \r<BR>\n" );
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document.write( "= (c^2-a^2)/(c-a) = c+a<BR>\n" );
document.write( "That is the slope.<BR>\n" );
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document.write( "Form of the line: y = mx + k where k is the y-intercept.<BR>\n" );
document.write( "a^2 = (c+a)(a) + k<BR>\n" );
document.write( "a^2 = ca+a^2 = k<BR>\n" );
document.write( "k = -ca (that is the y-intercept)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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