document.write( "Question 683186: what is the vertex form of y=3x^2-24x +21 \n" ); document.write( "
Algebra.Com's Answer #423483 by nerdybill(7384)\"\" \"About 
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what is the vertex form of y=3x^2-24x +21
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\n" ); document.write( "We can find it by \"completing the square\":
\n" ); document.write( "y=3x^2-24x +21
\n" ); document.write( "group x's:
\n" ); document.write( "y=(3x^2-24x) +21
\n" ); document.write( "factor out a 3:
\n" ); document.write( "y=3(x^2-8x) +21
\n" ); document.write( "complete square:
\n" ); document.write( "y=3(x^2-8x+16) +21 - (3*16)
\n" ); document.write( "y=3(x^2-8x+16) +21 - 48
\n" ); document.write( "y=3(x^2-8x+16) - 27
\n" ); document.write( "y=3(x-4)^2 - 27 (this is the vertex form)\r
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