document.write( "Question 388023: solve x+y=13 and x*y=40.find x and y \n" ); document.write( "

Algebra.Com's Answer #274339 by Fombitz(32388) $\"\"$ $\"About$

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1. $\"x%2By=13\"$
\n" ); document.write( "2. $\"xy=40\"$
\n" ); document.write( "From eq. 1,
\n" ); document.write( " $\"x=13-y\"$
\n" ); document.write( "Substitute into eq. 2,
\n" ); document.write( " $\"%2813-y%29y=40\"$
\n" ); document.write( " $\"13y-y%5E2=40\"$
\n" ); document.write( " $\"y%5E2-13y%2B40=0\"$
\n" ); document.write( " $\"%28y-5%29%28y-8%29=0\"$
\n" ); document.write( "Two solutions:
\n" ); document.write( " $\"y-5=0\"$
\n" ); document.write( " $\"y=5\"$
\n" ); document.write( "Then from eq. 2,
\n" ); document.write( " $\"x%285%29=40\"$
\n" ); document.write( " $\"x=8\"$
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\n" ); document.write( " $\"y-8=0\"$
\n" ); document.write( " $\"y=8\"$
\n" ); document.write( " $\"x%288%29=40\"$
\n" ); document.write( " $\"x=5\"$
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