document.write( "Question 1009335: What must be added to x2^-7x to make it a perfect square? \n" ); document.write( "

Algebra.Com's Answer #624852 by MathLover1(20850) $\"\"$ $\"About$

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\n" ); document.write( "\n" ); document.write( " $\"+x%5E2-7x\"$ .......recall: $\"%28a-b%29%5E2=a%5E2-2ab%2Bb%5E2\"$ ; so, to make it perfect square we need to add $\"b%5E2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+x%5E2-7x%2Bb%5E2\"$ ...when you compare it to $\"a%5E2-2ab%2Bb%5E2\"$ , you see that $\"a=1\"$ and $\"2ab=7\"$ \r
\n" ); document.write( "\n" ); document.write( "now we can find $\"b\"$ :\r
\n" ); document.write( "\n" ); document.write( " $\"2ab=7\"$ => $\"2%2A1%2Ab=7\"$ => $\"b=7%2F2\"$ \r
\n" ); document.write( "\n" ); document.write( "then we have:\r
\n" ); document.write( "\n" ); document.write( " $\"+x%5E2-7x%2B%287%2F2%29%5E2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+%28x-7%2F2%29%5E2\"$ \r
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