document.write( "Question 894316: If x-y = 7, xy= -8, What is the value of x^2 + 3xy + y^2 ? \n" ); document.write( "

Algebra.Com's Answer #541924 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"%28x-y%29%5E2=x%5E2-2xy%2By%5E2\"$
\n" ); document.write( "So then,
\n" ); document.write( " $\"%28x-y%29%5E2%2B5xy=x%5E2-2xy%2By%5E2%2B5xy\"$
\n" ); document.write( " $\"%28x-y%29%5E2%2B5xy=x%5E2%2B3xy%2By%5E2\"$
\n" ); document.write( "Substituting,
\n" ); document.write( " $\"x%5E2%2B3xy%2By%5E2=7%5E2%2B5%28-8%29\"$
\n" ); document.write( " $\"x%5E2%2B3xy%2By%5E2=49-40\"$
\n" ); document.write( " $\"x%5E2%2B3xy%2By%5E2=9\"$ \n" ); document.write( "

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