document.write( "Question 308383: how do i solve 12 x ² +19 x=21 by completing the square and using the formula a(x-h)²+k \n" ); document.write( "

Algebra.Com's Answer #220493 by Fombitz(32388) $\"\"$ $\"About$

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$\"12x%5E2%2B19x=21\"$
\n" ); document.write( "Factor out the 12 from the left hand side,
\n" ); document.write( " $\"12%28x%5E2%2B%2819%2F12%29x%29=21\"$
\n" ); document.write( "Take (1/2) of the x-coefficient and square it.
\n" ); document.write( "Add it to both sides (remember to multiply by 12 for the right hand side).
\n" ); document.write( " $\"%281%2F2%29%2819%2F12%29=19%2F24\"$
\n" ); document.write( " $\"%2819%2F24%29%5E2=361%2F576\"$
\n" ); document.write( " $\"12%28x%5E2%2B%2819%2F12%29x%2B361%2F576%29=21%2B12%28361%2F576%29\"$
\n" ); document.write( " $\"12%28x%2B19%2F24%29%5E2=1008%2F48%2B%28361%2F48%29\"$
\n" ); document.write( " $\"12%28x%2B19%2F24%29%5E2=1369%2F48\"$
\n" ); document.write( " $\"12%28x%2B19%2F24%29%5E2-1369%2F48=0\"$
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\n" ); document.write( "The vertex occurs at
\n" ); document.write( "(-19/24,-1369/48)or approximately (-0.8,-28.5) \n" ); document.write( "

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