document.write( "Question 192072: Find the exact vertex of the parabola algebraically...\r
\n" ); document.write( "\n" ); document.write( "f(x) = -3x^2 + 5x + 1
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Algebra.Com's Answer #144124 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
f(x) = -3x^2 + 5x + 1
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\n" ); document.write( "Use completing the square:
\n" ); document.write( "3x^2 -5x + ? = -y + 1 + ?
\n" ); document.write( "3(x^2 - (5/3)x + (5/6)^2) = -y + 1 +3(5/6)^2
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\n" ); document.write( "3(x-(5/3))^2 = -y + 1 + (25/12)
\n" ); document.write( "3(x-(5/3))^2 = -y + (37/12)
\n" ); document.write( "3(x-(5/3))^2 = -(y - (37/12)
\n" ); document.write( "(x-(5/3))^2 = (-1/3)(y-(37/12))
\n" ); document.write( "Vertex: (5/3 , 37/12)
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\n" ); document.write( "Graph:
\n" ); document.write( "\"graph%28400%2C300%2C-10%2C10%2C-10%2C10%2C-3x%5E2%2B5x%2B1%29\"
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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