document.write( "Question 404857: Solve for unknown:\r
\n" ); document.write( "\n" ); document.write( "3x-4y=10
\n" ); document.write( "4x-3y=5 \r
\n" ); document.write( "\n" ); document.write( "(I used the method of interchangeable coefficients but not getting the answer) \n" ); document.write( "

Algebra.Com's Answer #286109 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"3x+-+4y+=+10\"$
\n" ); document.write( " $\"4x+-+3y+=+5\"$
\n" ); document.write( "I think I would multiply the top equation by $\"-%283%2F4%29\"$
\n" ); document.write( " $\"-%289%2F4%29%2Ax+%2B+3y+=+-+15%2F2\"$
\n" ); document.write( " $\"4x+-+3y+=+5\"$ (now add)
\n" ); document.write( " $\"-%289%2F4%29%2Ax+%2B+4x+=+10%2F2+-+15%2F2\"$
\n" ); document.write( " $\"%2816%2F4+-+9%2F4%29%2Ax+=+-+5%2F2\"$
\n" ); document.write( " $\"%287%2F4%29%2Ax+=+-10%2F4\"$
\n" ); document.write( " $\"7x+=+-10\"$
\n" ); document.write( " $\"x+=+-10%2F7\"$
\n" ); document.write( "Substitute this in the top equation:
\n" ); document.write( " $\"-30%2F7+-+4y+=+70%2F7\"$
\n" ); document.write( " $\"-30+-+28y+=+70\"$
\n" ); document.write( " $\"28y+=+-100\"$
\n" ); document.write( " $\"y+=+-25%2F7\"$
\n" ); document.write( "I'll check the 2nd equation:
\n" ); document.write( " $\"4x+-+3y+=+5\"$
\n" ); document.write( " $\"4%28-10%2F7%29+-+3%28-25%2F7%29+=+5\"$
\n" ); document.write( " $\"-40%2F7+%2B+75%2F7+=+35%2F7\"$
\n" ); document.write( " $\"35%2F7+=+35%2F7\"$
\n" ); document.write( "OK
\n" ); document.write( "You can check 1st\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( " \n" ); document.write( "

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