document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1179372>Question 1179372</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the value of y such that the points are collinear.<BR>\n" );
document.write( "(−6, −4), (0, y), (−3, −3) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #808924 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=808924\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Solving the problem using formal mathematics as the other tutor did is good practice in some basic algebra, involving the slope of a line.<br><BR>\n" );
document.write( "But your understanding of math will be much stronger if, instead of plugging numbers into formulas, you UNDERSTAND what the formal mathematics is doing for you.<br><BR>\n" );
document.write( "The three points are supposed to be collinear, meaning the slope between pairs of points is the same.<BR>\n" );
document.write( "The informal definition of slope is \"rise over run\", or change in y divided by change in x.<BR>\n" );
document.write( "Arranged left to right, the three points are (-6,-4), (-3,-3), and (0,y).<BR>\n" );
document.write( "From the first point to the second, the run is 3 (from -6 to -3) and the rise is 1 (from -4 to -3).<BR>\n" );
document.write( "From the second point to the third, the run is also 3 (from -3 to 0); since the slopes are the same, the rise has to be 1.<BR>\n" );
document.write( "A rise of 1 from y=-3 puts you at y=-2.<br><BR>\n" );
document.write( "ANSWER: at x=0, y is -2.<br><BR>\n" );
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