document.write( "Question 621893: What value of c makes the polynomial below a perfect square?
\n" ); document.write( " 4x^2+12x+c \n" ); document.write( "

Algebra.Com's Answer #391044 by KMST(5328) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+4x%5E2\"$ is the square of $\"2x\"$
\n" ); document.write( " $\"%282x%2Bb%29%5E2=4x%5E2%2B4bx%2Bb%5E2\"$
\n" ); document.write( "If $\"4bx=12x\"$
\n" ); document.write( "no matter what value x takes, it must be
\n" ); document.write( " $\"4b=12\"$ <---> $\"b=3\"$ and then
\n" ); document.write( " $\"%282x%2Bb%29%5E2=%282x%2B3%29%5E2=4x%5E2%2B12x%2B3%5E2=4x%5E2%2B12x%2B9\"$
\n" ); document.write( "So $\"highlight%28c=9%29\"$ \n" ); document.write( "

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