document.write( "Question 887363: Write the equation of a parabola, in standard form, that goes through these points:
\n" ); document.write( "(0, 3) (1, 4) (-1, -6)\r
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\n" ); document.write( "\n" ); document.write( "Graph the parabola above. Indicate the vertex and axis of symmetry.
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Algebra.Com's Answer #536577 by josgarithmetic(39617)\"\" \"About 
You can put this solution on YOUR website!
\"ax%5E2%2Bbx%2Bc=y\"\r
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\n" ); document.write( "\"0%2B0%2Bc=3\"
\n" ); document.write( "\"a%2A1%2Bb%2A1%2Bc=4\"
\n" ); document.write( "\"a%28-1%29%5E2%2Bb%28-1%29%2Bc=-6\"
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\n" ); document.write( "\"0%2B0%2Bc=3\"
\n" ); document.write( "\"a%2Bb%2Bc=4\"
\n" ); document.write( "\"a-b%2Bc=-6\"
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\n" ); document.write( "\n" ); document.write( "The variables in this now become a, b, c.
\n" ); document.write( "The y-intercept point and its equation allow eliminating c so you can form two equations in just the unknowns a and b.\r
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\n" ); document.write( "\n" ); document.write( "You already see \"highlight%28c=3%29\".\r
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\n" ); document.write( "\n" ); document.write( "\"a%2Bb=4-c=4-3\", \"highlight_green%28a%2Bb=1%29\".\r
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\n" ); document.write( "\n" ); document.write( "\"a-b=-6-c=-6-3\", \"highlight_green%28a-b=-9%29\".\r
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\n" ); document.write( "\n" ); document.write( "Add those two and you can solve for a.
\n" ); document.write( "\"highlight%28a=-5%29\".\r
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\n" ); document.write( "\n" ); document.write( "Use either of the a & b equations to find b.
\n" ); document.write( "\"a%2Bb=1\"
\n" ); document.write( "\"b=1-a\"
\n" ); document.write( "\"b=1-%28-5%29\"
\n" ); document.write( "\"highlight%28b=6%29\".\r
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\n" ); document.write( "\n" ); document.write( "General equation now, \"highlight%28y=-5x%5E2%2B6x%2B3%29\".
\n" ); document.write( "Is that factorable?
\n" ); document.write( "Discriminant, \"6%2A6-4%2A%28-5%29%2A3=36%2B60=96\", quadratic is NOT factorable.\r
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\n" ); document.write( "\n" ); document.write( "You still want the vertex maximum point in order to be able to graph y.
\n" ); document.write( "You have your choice of completing the square to convert into standard form; or you can use the general solution of a quadratic equation to find the zeros and the vertex will be in the exact middle of the two solutions.\r
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\n" ); document.write( "\n" ); document.write( "This may help: Completing the Square to Solve General Quadratic Equation
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