document.write( "Question 64380: Please help me use completing the sq. to write the equation in the form y=a(x-h)^2+k. Also identify the vertex, focus and directrix.
\n" ); document.write( "y=3x^2=12x=1.\r
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Algebra.Com's Answer #45045 by stanbon(75887)\"\" \"About 
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Please help me use completing the sq. to write the equation in the form y=a(x-h)^2+k. Also identify the vertex, focus and directrix.
\n" ); document.write( "y=3x^2=12x=1.
\n" ); document.write( "Comment: You probably posted this with a mistake. I'm going to
\n" ); document.write( "assume you meant y=3x^2+12x+1
\n" ); document.write( "Rewrite as:
\n" ); document.write( "3x^2+12x=y-1
\n" ); document.write( "3(x^2+4x = y-1
\n" ); document.write( "x^2+4x+? = (1/3)(y-1)+?
\n" ); document.write( "Complete the square to get:
\n" ); document.write( "x^2+4x+4=(1/3)(y-1)+4
\n" ); document.write( "(x+2)^2=(1/3)(y-1+12)
\n" ); document.write( "(x+2)^2=(1/3)(y+11)
\n" ); document.write( "Vertex: (-2,-11)
\n" ); document.write( "4p=1/3
\n" ); document.write( "p=1/12
\n" ); document.write( "Focus: (-2+1/12,-11) = (-23/12,-11)
\n" ); document.write( "Directrix: y=-11-1/12 = -(11 1/12)
\n" ); document.write( "\"graph%28300%2C200%2C-10%2C10%2C-20%2C20%2C3x%5E2%2B12x%2B1%29\"
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.\r
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