document.write( "Question 978084: Graph y=3x^2 -12x-3
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\n" ); document.write( "Please help me with this problem
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Algebra.Com's Answer #599586 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\"+y=3x%5E2+-12x-3+\"\r
\n" ); document.write( "\n" ); document.write( "to graph it, you need several points\r
\n" ); document.write( "\n" ); document.write( "so, make a table\r
\n" ); document.write( "\n" ); document.write( "\"x\"|\"y\"......choose several values for \"x\" and calculate \"y\"\r
\n" ); document.write( "\n" ); document.write( "\"-1\"|\"12\"....\"+y=3%2A%28-1%29%5E2+-12%28-1%29-3=3%2A1%2B12-3=12+\"\r
\n" ); document.write( "\n" ); document.write( "\"0\"|\"-3\"....\"+y=3%2A%280%29%5E2+-12%280%29-3=-3+\"\r
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\n" ); document.write( "\n" ); document.write( "\"1\"|\"-12\"....\"+y=3%2A%281%29%5E2+-12%281%29-3=3%2A1-12-3=-12+\"\r
\n" ); document.write( "\n" ); document.write( "\"2\"|\"-15\"....\"+y=3%2A%282%29%5E2+-12%282%29-3=12-24-3=-12-3=-15+\"\r
\n" ); document.write( "\n" ); document.write( "\"3\"|\"-12\"....\"+y=3%2A%283%29%5E2+-12%283%29-3=27-36-3=-12+\"
\n" ); document.write( "plot these points and draw a parabola through:\r
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\n" ); document.write( "\n" ); document.write( "compare \"+y=3x%5E2+-12x-3+\" to \"+y=ax%5E2+%2Bbx%2Bc+\", you see that \"a=3\" and \"b=-12\"\r
\n" ); document.write( "\n" ); document.write( "since the \"x\" coordinate of the vertex is \"-b%2F2a\", we have\r
\n" ); document.write( "\n" ); document.write( "\"-b%2F2a=-%28-12%29%2F%282%2A3%29=12%2F6=2\"\r
\n" ); document.write( "\n" ); document.write( "so,\"x=2\"\r
\n" ); document.write( "\n" ); document.write( "substitute it in \"+y=3x%5E2+-12x-3+\" and calculate the \"y\" coordinate of the vertex\r
\n" ); document.write( "\n" ); document.write( "\"+y=3%2A%282%29%5E2+-12%282%29-3\"
\n" ); document.write( "\"y=12-24-3\"
\n" ); document.write( "\"y=-12-3\"
\n" ); document.write( "\"y=-15+\"\r
\n" ); document.write( "\n" ); document.write( "so, the vertex is at (\"2\",\"-15\")\r
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