document.write( "Question 548133: solve by substitution
\n" ); document.write( "2x + 4y = 8
\n" ); document.write( "-2x + y = 12 \n" ); document.write( "

Algebra.Com's Answer #356726 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
(1) $\"+2x+%2B+4y+=+8+\"$
\n" ); document.write( "(2) $\"+-2x+%2B+y+=+12+\"$
\n" ); document.write( "---------------
\n" ); document.write( "Divide both sides of (1) by $\"2\"$
\n" ); document.write( "(1) $\"+x+%2B+2y+=+4+\"$
\n" ); document.write( "(1) $\"+x+=+-2y+%2B+4+\"$
\n" ); document.write( "----------------
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+-2%2A%28-2y+%2B+4%29+%2B+y+=+12+\"$
\n" ); document.write( "(2) $\"+4y+-+8+%2B+y+=+12+\"$
\n" ); document.write( "(2) $\"+5y+=+20+\"$
\n" ); document.write( "(2) $\"+y+=+4+\"$
\n" ); document.write( "--------------
\n" ); document.write( "And, since
\n" ); document.write( "(2) $\"+-2x+%2B+4+=+12+\"$
\n" ); document.write( "(2) $\"+-2x+=+12+-+4+\"$
\n" ); document.write( "(2) $\"+-2x+=+8+\"$
\n" ); document.write( "(2) $\"+x+=+-4+\"$
\n" ); document.write( "--------------
\n" ); document.write( "The solution is ( -4, 4 )
\n" ); document.write( "check answer:
\n" ); document.write( "(2) $\"+-2x+%2B+y+=+12+\"$
\n" ); document.write( "(2) $\"+-2%2A%28-4%29+%2B+4+=+12+\"$
\n" ); document.write( "(2) $\"+8+%2B+4+=+12+\"$
\n" ); document.write( "(20 $\"+12+=+12+\"$
\n" ); document.write( "OK
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+x+%2B+2y+=+4+\"$
\n" ); document.write( "(1) $\"+-4+%2B+2%2A4+=+4+\"$
\n" ); document.write( "(1) $\"+-4+%2B+8+=+4+\"$
\n" ); document.write( "(1) $\"+4+=+4+\"$
\n" ); document.write( "OK \n" ); document.write( "

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