document.write( "Question 128883: please help me graph this equation 3x-y=9 thank you \n" ); document.write( "
Algebra.Com's Answer #94260 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "\n" ); document.write( "\"3x-y=9\" Start with the given equation\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-y=9-3x\" Subtract \"3+x\" from both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-y=-3x%2B9\" Rearrange the equation\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%28-3x%2B9%29%2F%28-1%29\" Divide both sides by \"-1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%28-3%2F-1%29x%2B%289%29%2F%28-1%29\" Break up the fraction\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=3x-9\" Reduce\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Looking at \"y=3x-9\" we can see that the equation is in slope-intercept form \"y=mx%2Bb\" where the slope is \"m=3\" and the y-intercept is \"b=-9\" \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since \"b=-9\" this tells us that the y-intercept is .Remember the y-intercept is the point where the graph intersects with the y-axis\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So we have one point \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now since the slope is comprised of the \"rise\" over the \"run\" this means\r
\n" ); document.write( "\n" ); document.write( "\"slope=rise%2Frun\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Also, because the slope is \"3\", this means:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"rise%2Frun=3%2F1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "which shows us that the rise is 3 and the run is 1. This means that to go from point to point, we can go up 3 and over 1\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So starting at , go up 3 units \r
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "and to the right 1 unit to get to the next point \r
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now draw a line through these points to graph \"y=3x-9\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So this is the graph of \"y=3x-9\" through the points and \r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );