document.write( "Question 1135200: Find a negative real number such that the square of the sum of the number and 21 is equal to 144
\n" ); document.write( " (If there are two correct answers, either answer can be entered.) \n" ); document.write( "

Algebra.Com's Answer #752760 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+n+\"$ = the negative real number
\n" ); document.write( " $\"+%28+n+%2B+21+%29%5E2+=+144+\"$
\n" ); document.write( " $\"+n%5E2+%2B+42n+%2B+441+=+144+\"$
\n" ); document.write( " $\"+n%5E2+%2B+42n+=+-297+\"$
\n" ); document.write( "complete the square
\n" ); document.write( " $\"+n%5E2+%2B+42n+%2B+%2842%2F2%29%5E2+=+-297+%2B+%2842%2F2%29%5E2+\"$
\n" ); document.write( " $\"+n%5E2+%2B+42n+%2B+441+=+144+\"$ ( what I started with )
\n" ); document.write( " $\"+%28+n+%2B+21+%29%5E2+=+12%5E2+\"$
\n" ); document.write( " $\"+n+%2B+21+=+12+\"$
\n" ); document.write( " $\"+n+=+-9+\"$
\n" ); document.write( "and also:
\n" ); document.write( " $\"+%28+n+%2B+21+%29%5E2+=+%28-12%29%5E2+\"$
\n" ); document.write( " $\"+n+%2B+21+=+-12+\"$
\n" ); document.write( " $\"+n+=+-33+\"$
\n" ); document.write( "-----------------------------
\n" ); document.write( "check the answers:
\n" ); document.write( " $\"+%28+n+%2B+21+%29%5E2+=+144+\"$
\n" ); document.write( " $\"+%28+-9+%2B+21+%29%5E2+=+12%5E2+\"$
\n" ); document.write( " $\"+12%5E2+=+12%5E2+\"$
\n" ); document.write( "OK
\n" ); document.write( " $\"+%28+-33+%2B+21+%29%5E2+=+12%5E2+\"$
\n" ); document.write( " $\"+%28-12%29%5E2+=+12%5E2+\"$
\n" ); document.write( " $\"+144+=+144+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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